Merge "Fix caching for SubmitRecords in ChangeData"
diff --git a/Documentation/config-gerrit.txt b/Documentation/config-gerrit.txt
index 91fe24b..23720460 100644
--- a/Documentation/config-gerrit.txt
+++ b/Documentation/config-gerrit.txt
@@ -5189,6 +5189,13 @@
 +
 By default 50.
 
+[[suggest.skipServiceUsers]]suggest.skipServiceUsers::
++
+If link:access-control.html#service_users[service users] should be skipped when
+suggesting reviewers.
++
+By default true.
+
 [[tracing]]
 === Section tracing
 
diff --git a/Documentation/js_licenses.txt b/Documentation/js_licenses.txt
index 48e729f..7ef9473 100644
--- a/Documentation/js_licenses.txt
+++ b/Documentation/js_licenses.txt
@@ -247,6 +247,38 @@
 ----
 
 
+[[DefinitelyTyped]]
+DefinitelyTyped
+
+* @types/resize-observer-browser
+
+[[DefinitelyTyped_license]]
+----
+    MIT License
+
+    Copyright (c) Microsoft Corporation.
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE
+
+----
+
+
 [[Polymer-2014]]
 Polymer-2014
 
diff --git a/Documentation/licenses.txt b/Documentation/licenses.txt
index b7cdf8a..5f0fb65 100644
--- a/Documentation/licenses.txt
+++ b/Documentation/licenses.txt
@@ -3204,6 +3204,38 @@
 ----
 
 
+[[DefinitelyTyped]]
+DefinitelyTyped
+
+* @types/resize-observer-browser
+
+[[DefinitelyTyped_license]]
+----
+    MIT License
+
+    Copyright (c) Microsoft Corporation.
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE
+
+----
+
+
 [[Polymer-2014]]
 Polymer-2014
 
diff --git a/Documentation/rest-api-config.txt b/Documentation/rest-api-config.txt
index 9764c8a..a8d9b3d 100644
--- a/Documentation/rest-api-config.txt
+++ b/Documentation/rest-api-config.txt
@@ -1839,6 +1839,8 @@
 Whether to enable the web UI for editing GPG keys.
 |`report_bug_url`    |optional|
 link:config-gerrit.html#gerrit.reportBugUrl[URL to report bugs].
+|`instance_id`       |optional|
+link:config-gerrit.html#gerrit.instanceId[Short identifier for this Gerrit installation].
 |=================================
 
 [[index-config-info]]
diff --git a/Documentation/user-search.txt b/Documentation/user-search.txt
index e02dc21..52c282e 100644
--- a/Documentation/user-search.txt
+++ b/Documentation/user-search.txt
@@ -190,6 +190,13 @@
 +
 Changes occurring in projects starting with 'PREFIX'.
 
+[[parentof]]
+parentof:'ID'::
+Changes which are parent to the change specified by 'ID'. Change 'ID' can be
+specified as a legacy numerical 'ID' such as 15183, or a Change-Id that can be
+picked from the commit message. This operator will return immediate parents
+and will not return grand parents or higher level ancestors of the given change.
+
 [[parentproject]]
 parentproject:'PROJECT'::
 +
diff --git a/java/com/google/gerrit/extensions/common/ActionInfo.java b/java/com/google/gerrit/extensions/common/ActionInfo.java
index 6ab80b2..2144ed5 100644
--- a/java/com/google/gerrit/extensions/common/ActionInfo.java
+++ b/java/com/google/gerrit/extensions/common/ActionInfo.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.extensions.common;
 
 import com.google.gerrit.extensions.webui.UiAction;
+import java.util.Objects;
 
 /**
  * Representation of an action in the REST API.
@@ -55,4 +56,23 @@
     title = d.getTitle();
     enabled = d.isEnabled() ? true : null;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof ActionInfo) {
+      ActionInfo actionInfo = (ActionInfo) o;
+      return Objects.equals(method, actionInfo.method)
+          && Objects.equals(label, actionInfo.label)
+          && Objects.equals(title, actionInfo.title)
+          && Objects.equals(enabled, actionInfo.enabled);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(method, label, title, enabled);
+  }
+
+  protected ActionInfo() {}
 }
diff --git a/java/com/google/gerrit/extensions/common/ApprovalInfo.java b/java/com/google/gerrit/extensions/common/ApprovalInfo.java
index f95ddff..bf72e83 100644
--- a/java/com/google/gerrit/extensions/common/ApprovalInfo.java
+++ b/java/com/google/gerrit/extensions/common/ApprovalInfo.java
@@ -16,6 +16,7 @@
 
 import com.google.gerrit.common.Nullable;
 import java.sql.Timestamp;
+import java.util.Objects;
 
 /**
  * Representation of an approval in the REST API.
@@ -71,4 +72,23 @@
     this.date = date;
     this.tag = tag;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof ApprovalInfo) {
+      ApprovalInfo approvalInfo = (ApprovalInfo) o;
+      return super.equals(o)
+          && Objects.equals(tag, approvalInfo.tag)
+          && Objects.equals(value, approvalInfo.value)
+          && Objects.equals(date, approvalInfo.date)
+          && Objects.equals(postSubmit, approvalInfo.postSubmit)
+          && Objects.equals(permittedVotingRange, approvalInfo.permittedVotingRange);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(super.hashCode(), tag, value, date, postSubmit, permittedVotingRange);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/AttentionSetInfo.java b/java/com/google/gerrit/extensions/common/AttentionSetInfo.java
index f29d32b..ba865fb 100644
--- a/java/com/google/gerrit/extensions/common/AttentionSetInfo.java
+++ b/java/com/google/gerrit/extensions/common/AttentionSetInfo.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.extensions.common;
 
 import java.sql.Timestamp;
+import java.util.Objects;
 
 /**
  * Represents a single user included in the attention set. Used in the API. See {@link
@@ -36,4 +37,22 @@
     this.lastUpdate = lastUpdate;
     this.reason = reason;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof AttentionSetInfo) {
+      AttentionSetInfo attentionSetInfo = (AttentionSetInfo) o;
+      return Objects.equals(account, attentionSetInfo.account)
+          && Objects.equals(lastUpdate, attentionSetInfo.lastUpdate)
+          && Objects.equals(reason, attentionSetInfo.reason);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(account, lastUpdate, reason);
+  }
+
+  protected AttentionSetInfo() {}
 }
diff --git a/java/com/google/gerrit/extensions/common/AvatarInfo.java b/java/com/google/gerrit/extensions/common/AvatarInfo.java
index 75665a8..b620ac2 100644
--- a/java/com/google/gerrit/extensions/common/AvatarInfo.java
+++ b/java/com/google/gerrit/extensions/common/AvatarInfo.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.extensions.common;
 
+import java.util.Objects;
+
 /**
  * Representation of an avatar in the REST API.
  *
@@ -38,4 +40,20 @@
 
   /** The width of the avatar image in pixels. */
   public Integer width;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof AvatarInfo) {
+      AvatarInfo avatarInfo = (AvatarInfo) o;
+      return Objects.equals(url, avatarInfo.url)
+          && Objects.equals(height, avatarInfo.height)
+          && Objects.equals(width, avatarInfo.width);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(url, height, width);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/FetchInfo.java b/java/com/google/gerrit/extensions/common/FetchInfo.java
index eda84b1..4b1e941 100644
--- a/java/com/google/gerrit/extensions/common/FetchInfo.java
+++ b/java/com/google/gerrit/extensions/common/FetchInfo.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.extensions.common;
 
 import java.util.Map;
+import java.util.Objects;
 
 public class FetchInfo {
   public String url;
@@ -25,4 +26,22 @@
     this.url = url;
     this.ref = ref;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof FetchInfo) {
+      FetchInfo fetchInfo = (FetchInfo) o;
+      return Objects.equals(url, fetchInfo.url)
+          && Objects.equals(ref, fetchInfo.ref)
+          && Objects.equals(commands, fetchInfo.commands);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(url, ref, commands);
+  }
+
+  protected FetchInfo() {}
 }
diff --git a/java/com/google/gerrit/extensions/common/GerritInfo.java b/java/com/google/gerrit/extensions/common/GerritInfo.java
index 2ae6703..3265a00 100644
--- a/java/com/google/gerrit/extensions/common/GerritInfo.java
+++ b/java/com/google/gerrit/extensions/common/GerritInfo.java
@@ -23,4 +23,5 @@
   public Boolean editGpgKeys;
   public String reportBugUrl;
   public String primaryWeblinkName;
+  public String instanceId;
 }
diff --git a/java/com/google/gerrit/extensions/common/GpgKeyInfo.java b/java/com/google/gerrit/extensions/common/GpgKeyInfo.java
index 7a5c15b..d656f22 100644
--- a/java/com/google/gerrit/extensions/common/GpgKeyInfo.java
+++ b/java/com/google/gerrit/extensions/common/GpgKeyInfo.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.extensions.common;
 
 import java.util.List;
+import java.util.Objects;
 
 public class GpgKeyInfo {
   /**
@@ -43,4 +44,22 @@
 
   public Status status;
   public List<String> problems;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof GpgKeyInfo) {
+      GpgKeyInfo gpgKeyInfo = (GpgKeyInfo) o;
+      return Objects.equals(id, gpgKeyInfo.id)
+          && Objects.equals(fingerprint, gpgKeyInfo.fingerprint)
+          && Objects.equals(userIds, gpgKeyInfo.userIds)
+          && Objects.equals(status, gpgKeyInfo.status)
+          && Objects.equals(problems, gpgKeyInfo.problems);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(id, fingerprint, userIds, status, problems);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/LabelInfo.java b/java/com/google/gerrit/extensions/common/LabelInfo.java
index 76dd93d..44bcdaf 100644
--- a/java/com/google/gerrit/extensions/common/LabelInfo.java
+++ b/java/com/google/gerrit/extensions/common/LabelInfo.java
@@ -16,6 +16,7 @@
 
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 public class LabelInfo {
   public AccountInfo approved;
@@ -30,4 +31,37 @@
   public Short defaultValue;
   public Boolean optional;
   public Boolean blocking;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof LabelInfo) {
+      LabelInfo labelInfo = (LabelInfo) o;
+      return Objects.equals(approved, labelInfo.approved)
+          && Objects.equals(rejected, labelInfo.rejected)
+          && Objects.equals(recommended, labelInfo.recommended)
+          && Objects.equals(disliked, labelInfo.disliked)
+          && Objects.equals(all, labelInfo.all)
+          && Objects.equals(values, labelInfo.values)
+          && Objects.equals(value, labelInfo.value)
+          && Objects.equals(defaultValue, labelInfo.defaultValue)
+          && Objects.equals(optional, labelInfo.optional)
+          && Objects.equals(blocking, labelInfo.blocking);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(
+        approved,
+        rejected,
+        recommended,
+        disliked,
+        all,
+        values,
+        value,
+        defaultValue,
+        optional,
+        blocking);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/PluginDefinedInfo.java b/java/com/google/gerrit/extensions/common/PluginDefinedInfo.java
index 69bfa2c..e2b1c36 100644
--- a/java/com/google/gerrit/extensions/common/PluginDefinedInfo.java
+++ b/java/com/google/gerrit/extensions/common/PluginDefinedInfo.java
@@ -14,7 +14,24 @@
 
 package com.google.gerrit.extensions.common;
 
+import java.util.Objects;
+
 public class PluginDefinedInfo {
   public String name;
   public String message;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof PluginDefinedInfo) {
+      PluginDefinedInfo pluginDefinedInfo = (PluginDefinedInfo) o;
+      return Objects.equals(name, pluginDefinedInfo.name)
+          && Objects.equals(message, pluginDefinedInfo.message);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(name, message);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/PushCertificateInfo.java b/java/com/google/gerrit/extensions/common/PushCertificateInfo.java
index 9eed808..199dbd1 100644
--- a/java/com/google/gerrit/extensions/common/PushCertificateInfo.java
+++ b/java/com/google/gerrit/extensions/common/PushCertificateInfo.java
@@ -14,7 +14,24 @@
 
 package com.google.gerrit.extensions.common;
 
+import java.util.Objects;
+
 public class PushCertificateInfo {
   public String certificate;
   public GpgKeyInfo key;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof PushCertificateInfo) {
+      PushCertificateInfo pushCertificateInfo = (PushCertificateInfo) o;
+      return Objects.equals(certificate, pushCertificateInfo.certificate)
+          && Objects.equals(key, pushCertificateInfo.key);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(certificate, key);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/ReviewerUpdateInfo.java b/java/com/google/gerrit/extensions/common/ReviewerUpdateInfo.java
index eccdc64..37e1ceb 100644
--- a/java/com/google/gerrit/extensions/common/ReviewerUpdateInfo.java
+++ b/java/com/google/gerrit/extensions/common/ReviewerUpdateInfo.java
@@ -16,10 +16,28 @@
 
 import com.google.gerrit.extensions.client.ReviewerState;
 import java.sql.Timestamp;
+import java.util.Objects;
 
 public class ReviewerUpdateInfo {
   public Timestamp updated;
   public AccountInfo updatedBy;
   public AccountInfo reviewer;
   public ReviewerState state;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof ReviewerUpdateInfo) {
+      ReviewerUpdateInfo reviewerUpdateInfo = (ReviewerUpdateInfo) o;
+      return Objects.equals(updated, reviewerUpdateInfo.updated)
+          && Objects.equals(updatedBy, reviewerUpdateInfo.updatedBy)
+          && Objects.equals(reviewer, reviewerUpdateInfo.reviewer)
+          && Objects.equals(state, reviewerUpdateInfo.state);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(updated, updatedBy, reviewer, state);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/RevisionInfo.java b/java/com/google/gerrit/extensions/common/RevisionInfo.java
index f262901..ea61f31 100644
--- a/java/com/google/gerrit/extensions/common/RevisionInfo.java
+++ b/java/com/google/gerrit/extensions/common/RevisionInfo.java
@@ -17,6 +17,7 @@
 import com.google.gerrit.extensions.client.ChangeKind;
 import java.sql.Timestamp;
 import java.util.Map;
+import java.util.Objects;
 
 public class RevisionInfo {
   // ActionJson#copy(List, RevisionInfo) must be adapted if new fields are added that are not
@@ -34,4 +35,43 @@
   public String commitWithFooters;
   public PushCertificateInfo pushCertificate;
   public String description;
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof RevisionInfo) {
+      RevisionInfo revisionInfo = (RevisionInfo) o;
+      return isCurrent == revisionInfo.isCurrent
+          && Objects.equals(kind, revisionInfo.kind)
+          && _number == revisionInfo._number
+          && Objects.equals(created, revisionInfo.created)
+          && Objects.equals(uploader, revisionInfo.uploader)
+          && Objects.equals(ref, revisionInfo.ref)
+          && Objects.equals(fetch, revisionInfo.fetch)
+          && Objects.equals(commit, revisionInfo.commit)
+          && Objects.equals(files, revisionInfo.files)
+          && Objects.equals(actions, revisionInfo.actions)
+          && Objects.equals(commitWithFooters, revisionInfo.commitWithFooters)
+          && Objects.equals(pushCertificate, revisionInfo.pushCertificate)
+          && Objects.equals(description, revisionInfo.description);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(
+        isCurrent,
+        kind,
+        _number,
+        created,
+        uploader,
+        ref,
+        fetch,
+        commit,
+        files,
+        actions,
+        commitWithFooters,
+        pushCertificate,
+        description);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/SubmitRequirementInfo.java b/java/com/google/gerrit/extensions/common/SubmitRequirementInfo.java
index 3483de5..a13e645 100644
--- a/java/com/google/gerrit/extensions/common/SubmitRequirementInfo.java
+++ b/java/com/google/gerrit/extensions/common/SubmitRequirementInfo.java
@@ -18,9 +18,9 @@
 import java.util.Objects;
 
 public class SubmitRequirementInfo {
-  public final String status;
-  public final String fallbackText;
-  public final String type;
+  public String status;
+  public String fallbackText;
+  public String type;
 
   public SubmitRequirementInfo(String status, String fallbackText, String type) {
     this.status = status;
@@ -55,4 +55,6 @@
         .add("type", type)
         .toString();
   }
+
+  protected SubmitRequirementInfo() {}
 }
diff --git a/java/com/google/gerrit/extensions/common/TrackingIdInfo.java b/java/com/google/gerrit/extensions/common/TrackingIdInfo.java
index 0c5ed68..3d35e08 100644
--- a/java/com/google/gerrit/extensions/common/TrackingIdInfo.java
+++ b/java/com/google/gerrit/extensions/common/TrackingIdInfo.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.extensions.common;
 
+import java.util.Objects;
+
 public class TrackingIdInfo {
   public String system;
   public String id;
@@ -22,4 +24,20 @@
     this.system = system;
     this.id = id;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof TrackingIdInfo) {
+      TrackingIdInfo trackingIdInfo = (TrackingIdInfo) o;
+      return Objects.equals(system, trackingIdInfo.system) && Objects.equals(id, trackingIdInfo.id);
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(system, id);
+  }
+
+  protected TrackingIdInfo() {}
 }
diff --git a/java/com/google/gerrit/extensions/common/VotingRangeInfo.java b/java/com/google/gerrit/extensions/common/VotingRangeInfo.java
index 5c35a49..2f7e9e4 100644
--- a/java/com/google/gerrit/extensions/common/VotingRangeInfo.java
+++ b/java/com/google/gerrit/extensions/common/VotingRangeInfo.java
@@ -14,6 +14,8 @@
 
 package com.google.gerrit.extensions.common;
 
+import java.util.Objects;
+
 public class VotingRangeInfo {
   public int min;
   public int max;
@@ -22,4 +24,18 @@
     this.min = min;
     this.max = max;
   }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o instanceof VotingRangeInfo) {
+      VotingRangeInfo votingRangeInfo = (VotingRangeInfo) o;
+      return min == votingRangeInfo.min && max == votingRangeInfo.max;
+    }
+    return false;
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(min, max);
+  }
 }
diff --git a/java/com/google/gerrit/extensions/common/WebLinkInfo.java b/java/com/google/gerrit/extensions/common/WebLinkInfo.java
index 84fd970..ba12be0 100644
--- a/java/com/google/gerrit/extensions/common/WebLinkInfo.java
+++ b/java/com/google/gerrit/extensions/common/WebLinkInfo.java
@@ -64,4 +64,6 @@
         + target
         + "}";
   }
+
+  protected WebLinkInfo() {}
 }
diff --git a/java/com/google/gerrit/server/patch/AutoMerger.java b/java/com/google/gerrit/server/patch/AutoMerger.java
index fe915c5..ac37411 100644
--- a/java/com/google/gerrit/server/patch/AutoMerger.java
+++ b/java/com/google/gerrit/server/patch/AutoMerger.java
@@ -109,6 +109,7 @@
               ActionType.GIT_UPDATE,
               "createAutoMerge",
               () -> createAutoMergeCommit(repo, rw, ins, merge, mergeStrategy))
+          .defaultTimeoutMultiplier(2)
           .call();
     } catch (Exception e) {
       Throwables.throwIfUnchecked(e);
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index 68a90d2..4e3edcd 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -173,6 +173,7 @@
   public static final String FIELD_MESSAGE = "message";
   public static final String FIELD_OWNER = "owner";
   public static final String FIELD_OWNERIN = "ownerin";
+  public static final String FIELD_PARENTOF = "parentof";
   public static final String FIELD_PARENTPROJECT = "parentproject";
   public static final String FIELD_PATH = "path";
   public static final String FIELD_PENDING_REVIEWER = "pendingreviewer";
@@ -735,6 +736,16 @@
   }
 
   @Operator
+  public Predicate<ChangeData> parentof(String value) throws QueryParseException {
+    List<ChangeData> changes = parseChangeData(value);
+    List<Predicate<ChangeData>> or = new ArrayList<>(changes.size());
+    for (ChangeData c : changes) {
+      or.add(new ParentOfPredicate(value, c, args.repoManager));
+    }
+    return Predicate.or(or);
+  }
+
+  @Operator
   public Predicate<ChangeData> parentproject(String name) {
     return new ParentProjectPredicate(args.projectCache, args.childProjects, name);
   }
@@ -1560,14 +1571,18 @@
   }
 
   private List<Change> parseChange(String value) throws QueryParseException {
+    return asChanges(parseChangeData(value));
+  }
+
+  private List<ChangeData> parseChangeData(String value) throws QueryParseException {
     if (PAT_LEGACY_ID.matcher(value).matches()) {
       Optional<Change.Id> id = Change.Id.tryParse(value);
       if (!id.isPresent()) {
         throw error("Invalid change id " + value);
       }
-      return asChanges(args.queryProvider.get().byLegacyChangeId(id.get()));
+      return args.queryProvider.get().byLegacyChangeId(id.get());
     } else if (PAT_CHANGE_ID.matcher(value).matches()) {
-      List<Change> changes = asChanges(args.queryProvider.get().byKeyPrefix(parseChangeId(value)));
+      List<ChangeData> changes = args.queryProvider.get().byKeyPrefix(parseChangeId(value));
       if (changes.isEmpty()) {
         throw error("Change " + value + " not found");
       }
diff --git a/java/com/google/gerrit/server/query/change/ParentOfPredicate.java b/java/com/google/gerrit/server/query/change/ParentOfPredicate.java
new file mode 100644
index 0000000..e48d586
--- /dev/null
+++ b/java/com/google/gerrit/server/query/change/ParentOfPredicate.java
@@ -0,0 +1,62 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.common.collect.Sets;
+import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.exceptions.StorageException;
+import com.google.gerrit.index.query.Matchable;
+import com.google.gerrit.index.query.OperatorPredicate;
+import com.google.gerrit.server.git.GitRepositoryManager;
+import java.io.IOException;
+import java.util.Set;
+import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
+
+public class ParentOfPredicate extends OperatorPredicate<ChangeData>
+    implements Matchable<ChangeData> {
+  protected final Set<RevCommit> parents;
+
+  public ParentOfPredicate(String value, ChangeData change, GitRepositoryManager repoManager) {
+    super(ChangeQueryBuilder.FIELD_PARENTOF, value);
+    this.parents = getParents(change, repoManager);
+  }
+
+  @Override
+  public boolean match(ChangeData changeData) {
+    return changeData.patchSets().stream().anyMatch(ps -> parents.contains(ps.commitId()));
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+
+  protected Set<RevCommit> getParents(ChangeData change, GitRepositoryManager repoManager) {
+    PatchSet ps = change.currentPatchSet();
+    try (Repository repo = repoManager.openRepository(change.project());
+        RevWalk walk = new RevWalk(repo)) {
+      RevCommit c = walk.parseCommit(ps.commitId());
+      return Sets.newHashSet(c.getParents());
+    } catch (IOException e) {
+      throw new StorageException(
+          String.format(
+              "Loading commit %s for ps %d of change %d failed.",
+              ps.commitId(), ps.id().get(), ps.id().changeId().get()),
+          e);
+    }
+  }
+}
diff --git a/java/com/google/gerrit/server/restapi/change/ReviewersUtil.java b/java/com/google/gerrit/server/restapi/change/ReviewersUtil.java
index 2a55e41..38be27e 100644
--- a/java/com/google/gerrit/server/restapi/change/ReviewersUtil.java
+++ b/java/com/google/gerrit/server/restapi/change/ReviewersUtil.java
@@ -51,6 +51,7 @@
 import com.google.gerrit.server.account.AccountState;
 import com.google.gerrit.server.account.GroupBackend;
 import com.google.gerrit.server.account.GroupMembers;
+import com.google.gerrit.server.account.ServiceUserClassifier;
 import com.google.gerrit.server.change.ReviewerAdder;
 import com.google.gerrit.server.index.account.AccountField;
 import com.google.gerrit.server.index.account.AccountIndexCollection;
@@ -130,6 +131,7 @@
   private final IndexConfig indexConfig;
   private final AccountControl.Factory accountControlFactory;
   private final Provider<CurrentUser> self;
+  private final ServiceUserClassifier serviceUserClassifier;
 
   @Inject
   ReviewersUtil(
@@ -143,7 +145,8 @@
       AccountIndexCollection accountIndexes,
       IndexConfig indexConfig,
       AccountControl.Factory accountControlFactory,
-      Provider<CurrentUser> self) {
+      Provider<CurrentUser> self,
+      ServiceUserClassifier serviceUserClassifier) {
     this.accountLoaderFactory = accountLoaderFactory;
     this.accountQueryBuilder = accountQueryBuilder;
     this.accountIndexRewriter = accountIndexRewriter;
@@ -155,6 +158,7 @@
     this.indexConfig = indexConfig;
     this.accountControlFactory = accountControlFactory;
     this.self = self;
+    this.serviceUserClassifier = serviceUserClassifier;
   }
 
   public interface VisibilityControl {
@@ -200,13 +204,17 @@
             reviewerState, changeNotes, suggestReviewers, projectState, candidateList);
     logger.atFine().log("Sorted recommendations: %s", sortedRecommendations);
 
-    // Filter accounts by visibility and enforce limit
+    // Filter accounts by visibility, skip service users and enforce limit
     List<Account.Id> filteredRecommendations = new ArrayList<>();
     try (Timer0.Context ctx = metrics.filterVisibility.start()) {
       for (Account.Id reviewer : sortedRecommendations) {
         if (filteredRecommendations.size() >= limit) {
           break;
         }
+        if (suggestReviewers.isSkipServiceUsers()
+            && serviceUserClassifier.isServiceUser(reviewer)) {
+          continue;
+        }
         // Check if change is visible to reviewer and if the current user can see reviewer
         if (visibilityControl.isVisibleTo(reviewer)
             && accountControlFactory.get().canSee(reviewer)) {
diff --git a/java/com/google/gerrit/server/restapi/change/SuggestReviewers.java b/java/com/google/gerrit/server/restapi/change/SuggestReviewers.java
index e071c89..71ff493 100644
--- a/java/com/google/gerrit/server/restapi/change/SuggestReviewers.java
+++ b/java/com/google/gerrit/server/restapi/change/SuggestReviewers.java
@@ -31,6 +31,8 @@
 
   private static final int DEFAULT_MAX_SUGGESTED = 10;
 
+  private static final boolean DEFAULT_SKIP_SERVICE_USERS = true;
+
   protected final ReviewersUtil reviewersUtil;
 
   private final boolean suggestAccounts;
@@ -39,6 +41,7 @@
   protected int limit;
   protected String query;
   protected final int maxSuggestedReviewers;
+  protected boolean skipServiceUsers;
 
   @Option(
       name = "--limit",
@@ -78,6 +81,10 @@
     return maxAllowedWithoutConfirmation;
   }
 
+  public boolean isSkipServiceUsers() {
+    return skipServiceUsers;
+  }
+
   @Inject
   public SuggestReviewers(
       AccountVisibility av, @GerritServerConfig Config cfg, ReviewersUtil reviewersUtil) {
@@ -100,6 +107,9 @@
             ReviewerAdder.DEFAULT_MAX_REVIEWERS_WITHOUT_CHECK);
 
     logger.atFine().log("AccountVisibility: %s", av.name());
+
+    this.skipServiceUsers =
+        cfg.getBoolean("suggest", "skipServiceUsers", DEFAULT_SKIP_SERVICE_USERS);
   }
 
   public static GerritConfigListener configListener() {
diff --git a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
index 5459ede..0a5692e 100644
--- a/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
+++ b/java/com/google/gerrit/server/restapi/config/GetServerInfo.java
@@ -304,6 +304,7 @@
     info.editGpgKeys =
         toBoolean(enableSignedPush && config.getBoolean("gerrit", null, "editGpgKeys", true));
     info.primaryWeblinkName = config.getString("gerrit", null, "primaryWeblinkName");
+    info.instanceId = config.getString("gerrit", null, "instanceId");
     return info;
   }
 
diff --git a/java/com/google/gerrit/server/submit/MergeOp.java b/java/com/google/gerrit/server/submit/MergeOp.java
index b12a5b5..f486650 100644
--- a/java/com/google/gerrit/server/submit/MergeOp.java
+++ b/java/com/google/gerrit/server/submit/MergeOp.java
@@ -549,8 +549,8 @@
             .listener(retryTracker)
             // Up to the entire submit operation is retried, including possibly many projects.
             // Multiply the timeout by the number of projects we're actually attempting to
-            // submit.
-            .defaultTimeoutMultiplier(filteredNoteDbChangeSet.projects().size())
+            // submit. Times 2 to retry more persistently, to increase success rate.
+            .defaultTimeoutMultiplier(filteredNoteDbChangeSet.projects().size() * 2)
             // By default, we only retry lock failures. Here it's better to also retry unexpected
             // runtime exceptions.
             .retryOn(t -> t instanceof RuntimeException)
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/SuggestReviewersIT.java b/javatests/com/google/gerrit/acceptance/rest/change/SuggestReviewersIT.java
index 888878f..ffde622 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/SuggestReviewersIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/SuggestReviewersIT.java
@@ -450,6 +450,23 @@
   }
 
   @Test
+  public void suggestNoServiceAccounts() throws Exception {
+    requestScopeOperations.setApiUser(user.id());
+    String changeIdReviewed = createChangeFromApi();
+    String changeId = createChangeFromApi();
+
+    String name = name("foo");
+    TestAccount foo = accountCreator.create(name);
+    reviewChange(changeIdReviewed, foo);
+
+    assertReviewers(suggestReviewers(changeId, name), ImmutableList.of(foo), ImmutableList.of());
+
+    groupOperations.group(serviceUsersUUID()).forUpdate().addMember(foo.id()).update();
+
+    assertReviewers(suggestReviewers(changeId, name), ImmutableList.of(), ImmutableList.of());
+  }
+
+  @Test
   public void suggestNoExistingReviewers() throws Exception {
     requestScopeOperations.setApiUser(user.id());
     String changeId = createChangeFromApi();
@@ -608,6 +625,13 @@
     return user(name, fullName, name);
   }
 
+  private AccountGroup.UUID serviceUsersUUID() {
+    return groupCache
+        .get(AccountGroup.nameKey("Service Users"))
+        .orElseThrow(() -> new IllegalStateException("unable to find 'Service Users'"))
+        .getGroupUUID();
+  }
+
   private void reviewChange(String changeId, TestAccount reviewer) throws RestApiException {
     gApi.changes().id(changeId).addReviewer(reviewer.id().toString());
   }
diff --git a/javatests/com/google/gerrit/acceptance/rest/config/ServerInfoIT.java b/javatests/com/google/gerrit/acceptance/rest/config/ServerInfoIT.java
index 0a84db4..4738f64 100644
--- a/javatests/com/google/gerrit/acceptance/rest/config/ServerInfoIT.java
+++ b/javatests/com/google/gerrit/acceptance/rest/config/ServerInfoIT.java
@@ -74,6 +74,7 @@
   @GerritConfig(name = "gerrit.allProjects", value = "Root")
   @GerritConfig(name = "gerrit.allUsers", value = "Users")
   @GerritConfig(name = "gerrit.reportBugUrl", value = "https://example.com/report")
+  @GerritConfig(name = "gerrit.instanceId", value = "devops-instance")
 
   // suggest
   @GerritConfig(name = "suggest.from", value = "3")
@@ -116,6 +117,7 @@
     assertThat(i.gerrit.allProjects).isEqualTo("Root");
     assertThat(i.gerrit.allUsers).isEqualTo("Users");
     assertThat(i.gerrit.reportBugUrl).isEqualTo("https://example.com/report");
+    assertThat(i.gerrit.instanceId).isEqualTo("devops-instance");
 
     // plugin
     assertThat(i.plugin.jsResourcePaths).isEmpty();
@@ -184,6 +186,7 @@
     assertThat(i.gerrit.allProjects).isEqualTo(AllProjectsNameProvider.DEFAULT);
     assertThat(i.gerrit.allUsers).isEqualTo(AllUsersNameProvider.DEFAULT);
     assertThat(i.gerrit.reportBugUrl).isNull();
+    assertThat(i.gerrit.instanceId).isNull();
 
     // plugin
     assertThat(i.plugin.jsResourcePaths).isEmpty();
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index 7efcb4b..48bd321 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -705,6 +705,24 @@
   }
 
   @Test
+  public void byParentOf() throws Exception {
+    TestRepository<Repo> repo1 = createProject("repo1");
+    RevCommit commit1 = repo1.parseBody(repo1.commit().message("message").create());
+    Change change1 = insert(repo1, newChangeForCommit(repo1, commit1));
+    RevCommit commit2 = repo1.parseBody(repo1.commit(commit1));
+    Change change2 = insert(repo1, newChangeForCommit(repo1, commit2));
+    RevCommit commit3 = repo1.parseBody(repo1.commit(commit1, commit2));
+    Change change3 = insert(repo1, newChangeForCommit(repo1, commit3));
+
+    assertQuery("parentof:" + change1.getId().get());
+    assertQuery("parentof:" + change1.getKey().get());
+    assertQuery("parentof:" + change2.getId().get(), change1);
+    assertQuery("parentof:" + change2.getKey().get(), change1);
+    assertQuery("parentof:" + change3.getId().get(), change2, change1);
+    assertQuery("parentof:" + change3.getKey().get(), change2, change1);
+  }
+
+  @Test
   public void byParentProject() throws Exception {
     TestRepository<Repo> repo1 = createProject("repo1");
     TestRepository<Repo> repo2 = createProject("repo2", "repo1");
diff --git a/modules/jgit b/modules/jgit
index 4560bdf..9bfb0f3 160000
--- a/modules/jgit
+++ b/modules/jgit
@@ -1 +1 @@
-Subproject commit 4560bdf7e2e3c16a7c7bb3f2fcf067bb1eee26fb
+Subproject commit 9bfb0f3a4ec856dcbebb477a1ee8803a3c47c194
diff --git a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
index bd2781f..f2b4c89 100644
--- a/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
+++ b/polygerrit-ui/app/elements/admin/gr-admin-view/gr-admin-view.ts
@@ -99,7 +99,7 @@
     return htmlTemplate;
   }
 
-  private _account?: AccountDetailInfo;
+  private account?: AccountDetailInfo;
 
   @property({type: Object})
   params?: AdminViewParams;
@@ -189,7 +189,7 @@
       getPluginLoader().awaitPluginsLoaded(),
     ];
     return Promise.all(promises).then(result => {
-      this._account = result[0];
+      this.account = result[0];
       let options: AdminNavLinksOption | undefined = undefined;
       if (this._repoName) {
         options = {repoName: this._repoName};
@@ -204,7 +204,7 @@
       }
 
       return getAdminLinks(
-        this._account,
+        this.account,
         () =>
           this.restApiService.getAccountCapabilities().then(capabilities => {
             if (!capabilities) {
@@ -400,7 +400,7 @@
       }
       return '';
     }
-    // TODO(TS): The following condtion seems always false, because params
+    // TODO(TS): The following condition seems always false, because params
     // never has detailType property. Remove it.
     if (
       ((params as unknown) as AdminSubsectionLink).detailType &&
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
index 26ff799..56c5733 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
@@ -118,7 +118,7 @@
   @property({type: Boolean})
   _loading = true;
 
-  private _originalInheritsFrom?: ProjectInfo | null;
+  private originalInheritsFrom?: ProjectInfo | null;
 
   private readonly restApiService = appContext.restApiService;
 
@@ -173,7 +173,7 @@
               ...res.inherits_from,
             }
           : null;
-        this._originalInheritsFrom = res.inherits_from
+        this.originalInheritsFrom = res.inherits_from
           ? {
               ...res.inherits_from,
             }
@@ -306,7 +306,7 @@
     }
     // Restore inheritFrom.
     if (this._inheritsFrom) {
-      this._inheritsFrom = {...this._originalInheritsFrom};
+      this._inheritsFrom = {...this.originalInheritsFrom};
       this._inheritFromFilter =
         'name' in this._inheritsFrom ? this._inheritsFrom.name : undefined;
     }
@@ -446,8 +446,8 @@
       remove: {},
     };
 
-    const originalInheritsFromId = this._originalInheritsFrom
-      ? singleDecodeURL(this._originalInheritsFrom.id)
+    const originalInheritsFromId = this.originalInheritsFrom
+      ? singleDecodeURL(this.originalInheritsFrom.id)
       : null;
     // TODO(TS): this._inheritsFrom as ProjectInfo might be a mistake.
     // _inheritsFrom can be {}
diff --git a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_test.js b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_test.js
index b0065d9..9cc6357 100644
--- a/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_test.js
+++ b/polygerrit-ui/app/elements/admin/gr-rule-editor/gr-rule-editor_test.js
@@ -192,7 +192,7 @@
       };
       element.section = 'refs/*';
 
-      // Typically called on ready since elements will have properies defined
+      // Typically called on ready since elements will have properties defined
       // by the parent element.
       element._setupValues(element.rule);
       flush();
diff --git a/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help_html.ts b/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help_html.ts
index 9812933..add7ca5 100644
--- a/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help_html.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-create-change-help/gr-create-change-help_html.ts
@@ -36,7 +36,7 @@
       width: 10em;
     }
     #graphic iron-icon {
-      color: #9e9e9e;
+      color: var(--gray-foreground);
       height: 5em;
       width: 5em;
     }
diff --git a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
index 9240905..816c8ef 100644
--- a/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
+++ b/polygerrit-ui/app/elements/change-list/gr-dashboard-view/gr-dashboard-view.ts
@@ -58,7 +58,7 @@
 import {firePageError, fireTitleChange} from '../../../utils/event-util';
 import {GerritView} from '../../../services/router/router-model';
 
-const PROJECT_PLACEHOLDER_PATTERN = /\$\{project\}/g;
+const PROJECT_PLACEHOLDER_PATTERN = /\${project}/g;
 const RELOAD_DASHBOARD_INTERVAL_MS = 10 * 1000;
 
 export interface GrDashboardView {
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
index c3858d8..87b09c7 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions.ts
@@ -2068,10 +2068,10 @@
    *
    */
   _waitForChangeReachable(changeNum: NumericChangeId) {
-    let attempsRemaining = AWAIT_CHANGE_ATTEMPTS;
+    let attemptsRemaining = AWAIT_CHANGE_ATTEMPTS;
     return new Promise(resolve => {
       const check = () => {
-        attempsRemaining--;
+        attemptsRemaining--;
         // Pass a no-op error handler to avoid the "not found" error toast.
         this.restApiService
           .getChange(changeNum, () => {})
@@ -2082,7 +2082,7 @@
               return;
             }
 
-            if (attempsRemaining) {
+            if (attemptsRemaining) {
               this.async(check, AWAIT_CHANGE_TIMEOUT_MS);
             } else {
               resolve(false);
diff --git a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
index 6c9a27d..fbb70b7 100644
--- a/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
+++ b/polygerrit-ui/app/elements/change/gr-change-actions/gr-change-actions_test.js
@@ -2110,7 +2110,7 @@
 
       element = basicFixture.instantiate();
       // getChangeRevisionActions is not called without
-      // set the following properies
+      // set the following properties
       element.change = {};
       element.changeNum = '42';
       element.latestPatchNum = '2';
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
index c5c73c5..59bf8ad 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
@@ -78,7 +78,7 @@
     }
     .icon.help,
     .icon.notTrusted {
-      color: #ffa62f;
+      color: var(--warning-foreground);
     }
     .icon.invalid {
       color: var(--negative-red-text-color);
@@ -87,7 +87,7 @@
       color: var(--positive-green-text-color);
     }
     .parentList.notCurrent.nonMerge #parentNotCurrentMessage {
-      --arrow-color: #ffa62f;
+      --arrow-color: var(--warning-foreground);
       display: inline-block;
     }
     .separatedSection {
diff --git a/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements.ts b/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements.ts
index c0e87f3..adc7fd3 100644
--- a/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements.ts
@@ -37,6 +37,7 @@
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {appContext} from '../../../services/app-context';
 import {KnownExperimentId} from '../../../services/flags/flags';
+import {labelCompare} from '../../../utils/label-util';
 
 interface ChangeRequirement extends Requirement {
   satisfied: boolean;
@@ -136,7 +137,7 @@
     const labels = labelsRecord.base || {};
     const allLabels: Label[] = [];
 
-    for (const label of Object.keys(labels).sort()) {
+    for (const label of Object.keys(labels).sort(labelCompare)) {
       allLabels.push({
         labelName: label,
         icon: this._computeLabelIcon(labels[label]),
diff --git a/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements_html.ts b/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements_html.ts
index f172ccc..a502949 100644
--- a/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-requirements/gr-change-requirements_html.ts
@@ -23,7 +23,7 @@
       width: 100%;
     }
     .status {
-      color: #ffa62f;
+      color: var(--warning-foreground);
       display: inline-block;
       text-align: center;
       vertical-align: top;
@@ -99,6 +99,9 @@
       padding-left: 0;
     }
   </style>
+  <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
+    <h3 class="metadata-title">Submit requirements</h3>
+  </template>
   <template is="dom-repeat" items="[[_requirements]]">
     <gr-endpoint-decorator
       class="submit-requirement-endpoints"
@@ -126,9 +129,6 @@
       </div>
     </gr-endpoint-decorator>
   </template>
-  <template is="dom-if" if="[[_isNewChangeSummaryUiEnabled]]">
-    <h3 class="metadata-title">Submit requirements</h3>
-  </template>
   <template is="dom-repeat" items="[[_requiredLabels]]">
     <section>
       <div class="title">
diff --git a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
index 4af51a9..beec0a4 100644
--- a/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-summary/gr-change-summary.ts
@@ -56,7 +56,7 @@
 import {notUndefined} from '../../../types/types';
 import {uniqueDefinedAvatar} from '../../../utils/account-util';
 import {PrimaryTab} from '../../../constants/constants';
-import {CommentTabState} from '../../../types/events';
+import {ChecksTabState, CommentTabState} from '../../../types/events';
 
 export enum SummaryChipStyles {
   INFO = 'info',
@@ -229,19 +229,13 @@
     const chipClass = `checksChip font-small ${this.icon}`;
     const grIcon = `gr-icons:${this.icon}`;
     return html`
-      <div class="${chipClass}" role="button" @click="${this.handleClick}">
+      <div class="${chipClass}" role="button">
         <iron-icon icon="${grIcon}"></iron-icon>
         <div class="text">${this.text}</div>
         <slot></slot>
       </div>
     `;
   }
-
-  private handleClick(e: MouseEvent) {
-    e.stopPropagation();
-    e.preventDefault();
-    fireShowPrimaryTab(this, PrimaryTab.CHECKS);
-  }
 }
 
 /** What is the maximum number of expanded checks chips? */
@@ -325,7 +319,7 @@
     const icon = iconForCategory(category);
     const runs = this.runs.filter(run => hasResultsOf(run, category));
     const count = (run: CheckRun) => getResultsOf(run, category);
-    return this.renderChecksChip(icon, runs, count);
+    return this.renderChecksChip(icon, runs, category, count);
   }
 
   renderChecksChipForStatus(
@@ -334,12 +328,13 @@
   ) {
     const icon = iconForStatus(status);
     const runs = this.runs.filter(filter);
-    return this.renderChecksChip(icon, runs, () => []);
+    return this.renderChecksChip(icon, runs, status, () => []);
   }
 
   renderChecksChip(
     icon: string,
     runs: CheckRun[],
+    statusOrCategory: RunStatus | Category,
     resultFilter: (run: CheckRun) => CheckResult[]
   ) {
     if (runs.length === 0) {
@@ -359,9 +354,10 @@
           class="${icon}"
           .icon="${icon}"
           .text="${text}"
+          @click="${() => this.onChipClick({checkName: run.checkName})}"
           >${links.map(
             link => html`
-              <a href="${link.url}" target="_blank" @click="${this.onClick}"
+              <a href="${link.url}" target="_blank" @click="${this.onLinkClick}"
                 ><iron-icon class="launch" icon="gr-icons:launch"></iron-icon
               ></a>
             `
@@ -380,11 +376,18 @@
       class="${icon}"
       .icon="${icon}"
       .text="${sum}"
+      @click="${() => this.onChipClick({statusOrCategory})}"
     ></gr-checks-chip>`;
   }
 
-  private onClick(e: MouseEvent) {
-    // Prevents handleClick() from reacting to <a> link clicks.
+  private onChipClick(state: ChecksTabState) {
+    fireShowPrimaryTab(this, PrimaryTab.CHECKS, true, {
+      checksTab: state,
+    });
+  }
+
+  private onLinkClick(e: MouseEvent) {
+    // Prevents onChipClick() from reacting to <a> link clicks.
     e.stopPropagation();
   }
 
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
index f3fb860..08c04e8 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_html.ts
@@ -690,7 +690,10 @@
         is="dom-if"
         if="[[_isTabActive(_constants.PrimaryTab.CHECKS, _activeTabs)]]"
       >
-        <gr-checks-tab id="checksTab"></gr-checks-tab>
+        <gr-checks-tab
+          id="checksTab"
+          tab-state="[[_tabState.checksTab]]"
+        ></gr-checks-tab>
       </template>
       <template
         is="dom-if"
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
index a5c0624..c2947a6 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list.ts
@@ -803,7 +803,7 @@
   }
 
   /**
-   * Handle all events from the file list dom-repeat so event handleers don't
+   * Handle all events from the file list dom-repeat so event handlers don't
    * have to get registered for potentially very long lists.
    */
   _handleFileListClick(e: MouseEvent) {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
index 23718fa..c57a2d5 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_html.ts
@@ -154,7 +154,7 @@
       padding-left: var(--spacing-s);
     }
     .drafts {
-      color: #c62828;
+      color: var(--error-foreground);
       font-weight: var(--font-weight-bold);
     }
     .show-hide-icon:focus {
diff --git a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
index 285b73f..80d8729 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list/gr-file-list_test.js
@@ -1244,7 +1244,7 @@
       // are no deletions.
       assert.equal(element._computeBarAdditionWidth(file, stats), 30);
 
-      // If there are no insetions, there is no width.
+      // If there are no insertions, there is no width.
       stats.maxInserted = 0;
       assert.equal(element._computeBarAdditionWidth(file, stats), 0);
 
diff --git a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
index a966186..661cd1a 100644
--- a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
+++ b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.ts
@@ -37,6 +37,7 @@
 } from '../gr-label-score-row/gr-label-score-row';
 import {PolymerDeepPropertyChange} from '@polymer/polymer/interfaces';
 import {appContext} from '../../../services/app-context';
+import {labelCompare} from '../../../utils/label-util';
 
 @customElement('gr-label-scores')
 export class GrLabelScores extends GestureEventListeners(
@@ -147,7 +148,7 @@
     if (!labelRecord?.base) return [];
     const labelsObj = labelRecord.base;
     return Object.keys(labelsObj)
-      .sort()
+      .sort(labelCompare)
       .map(key => {
         return {
           name: key,
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
index 2fe409a..f913459 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
@@ -54,7 +54,7 @@
 } from '../../../utils/patch-set-util';
 import {isServiceUser} from '../../../utils/account-util';
 
-const PATCH_SET_PREFIX_PATTERN = /^(?:Uploaded\s*)?(?:P|p)atch (?:S|s)et \d+:\s*(.*)/;
+const PATCH_SET_PREFIX_PATTERN = /^(?:Uploaded\s*)?[Pp]atch [Ss]et \d+:\s*(.*)/;
 const LABEL_TITLE_SCORE_PATTERN = /^(-?)([A-Za-z0-9-]+?)([+-]\d+)?[.]?$/;
 const UPLOADED_NEW_PATCHSET_PATTERN = /Uploaded patch set (\d+)./;
 const MERGED_PATCHSET_PATTERN = /(\d+) is the latest approved patch-set/;
@@ -484,7 +484,7 @@
   _handleAnchorClick(e: Event) {
     e.preventDefault();
     // The element which triggers _handleAnchorClick is rendered only if
-    // message.id defined: the elemenet is wrapped in dom-if if="[[message.id]]"
+    // message.id defined: the element is wrapped in dom-if if="[[message.id]]"
     const detail: MessageAnchorTapDetail = {
       id: this.message!.id,
     };
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
index 9877a95..bc3f167 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
@@ -118,7 +118,7 @@
 
 /**
  * If messages have the same tag, then that influences grouping and whether
- * a message is initally hidden or not, see isImportant(). So we are applying
+ * a message is initially hidden or not, see isImportant(). So we are applying
  * some "magic" rules here in order to hide exactly the right messages.
  *
  * 1. If a message does not have a tag, but is associated with robot comments,
@@ -263,7 +263,7 @@
   _combinedMessages: CombinedMessage[] = [];
 
   @property({type: Object, computed: '_computeLabelExtremes(labels.*)'})
-  _labelExtremes: {[lableName: string]: VotingRangeInfo} = {};
+  _labelExtremes: {[labelName: string]: VotingRangeInfo} = {};
 
   private readonly reporting = appContext.reportingService;
 
@@ -466,7 +466,7 @@
       LabelNameToInfoMap
     >
   ) {
-    const extremes: {[lableName: string]: VotingRangeInfo} = {};
+    const extremes: {[labelName: string]: VotingRangeInfo} = {};
     const labels = labelRecord.base;
     if (!labels) {
       return extremes;
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-change.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-change.ts
index 3ed545e..7b698f1 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-change.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-change.ts
@@ -77,10 +77,10 @@
           margin-left: var(--spacing-xs);
         }
         .notCurrent {
-          color: #e65100;
+          color: var(--warning-foreground);
         }
         .indirectAncestor {
-          color: #33691e;
+          color: var(--indirect-ancestor-text-color);
         }
         .submittableCheck {
           padding-left: var(--spacing-s);
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
index c4b1917..e921979 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list-experimental/gr-related-changes-list-experimental.ts
@@ -81,6 +81,7 @@
       css`
         .note {
           color: var(--error-text-color);
+          margin-left: 1.2em;
         }
         section {
           margin-bottom: var(--spacing-m);
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
index 9941fa9..2f53319 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list_html.ts
@@ -66,10 +66,10 @@
       margin-left: var(--spacing-xs);
     }
     .notCurrent {
-      color: #e65100;
+      color: var(--warning-foreground);
     }
     .indirectAncestor {
-      color: #33691e;
+      color: var(--indirect-ancestor-text-color);
     }
     .submittableCheck {
       padding-left: var(--spacing-s);
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
index 705a402..a8e89b6 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
@@ -784,7 +784,7 @@
   }
 
   _handle400Error(r?: Response | null) {
-    if (!r) throw new Error('Reponse is empty.');
+    if (!r) throw new Error('Response is empty.');
     let response: Response = r;
     // A call to _saveReview could fail with a server error if erroneous
     // reviewers were requested. This is signalled with a 400 Bad Request
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
index 6682bfb..0575239 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog_test.js
@@ -1276,7 +1276,7 @@
         'Send and Start review');
   });
 
-  test('_handle400Error reviewrs and CCs', done => {
+  test('_handle400Error reviewers and CCs', done => {
     const error1 = 'error 1';
     const error2 = 'error 2';
     const error3 = 'error 3';
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-results.ts b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
index 34945a9..002c8c3 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-results.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
@@ -15,7 +15,14 @@
  * limitations under the License.
  */
 import {html} from 'lit-html';
-import {css, customElement, property, PropertyValues} from 'lit-element';
+import {
+  css,
+  customElement,
+  internalProperty,
+  property,
+  PropertyValues,
+  query,
+} from 'lit-element';
 import {GrLitElement} from '../lit/gr-lit-element';
 import {Category, CheckRun, Link, RunStatus, Tag} from '../../api/checks';
 import {sharedStyles} from '../../styles/shared-styles';
@@ -26,6 +33,8 @@
   iconForCategory,
   isRunning,
 } from '../../services/checks/checks-util';
+import {assertIsDefined} from '../../utils/common-util';
+import {whenVisible} from '../../utils/dom-util';
 
 @customElement('gr-result-row')
 class GrResultRow extends GrLitElement {
@@ -38,6 +47,9 @@
   @property({type: Boolean, reflect: true})
   isExpandable = false;
 
+  @property()
+  shouldRender = false;
+
   static get styles() {
     return [
       sharedStyles,
@@ -126,8 +138,26 @@
     super.update(changedProperties);
   }
 
+  firstUpdated() {
+    const loading = this.shadowRoot?.querySelector('.container');
+    assertIsDefined(loading, '"Loading" element');
+    whenVisible(loading, () => this.setAttribute('shouldRender', 'true'), 200);
+  }
+
   render() {
     if (!this.result) return '';
+    if (!this.shouldRender) {
+      return html`
+        <tr class="container">
+          <td class="iconCol"></td>
+          <td class="nameCol">
+            <div><span class="loading">Loading...</span></div>
+          </td>
+          <td class="summaryCol"></td>
+          <td class="expanderCol"></td>
+        </tr>
+      `;
+    }
     return html`
       <tr class="container" @click="${this.toggleExpanded}">
         <td class="iconCol">
@@ -256,9 +286,17 @@
 
 @customElement('gr-checks-results')
 export class GrChecksResults extends GrLitElement {
+  @query('#filterInput')
+  filterInput?: HTMLInputElement;
+
+  @internalProperty()
+  filterRegExp = new RegExp('');
+
   @property()
   runs: CheckRun[] = [];
 
+  private isSectionExpanded = new Map<Category | 'SUCCESS', boolean>();
+
   static get styles() {
     return [
       sharedStyles,
@@ -267,27 +305,45 @@
           display: block;
           padding: var(--spacing-xl);
         }
+        input#filterInput {
+          margin-top: var(--spacing-s);
+          padding: var(--spacing-s) var(--spacing-m);
+          min-width: 400px;
+        }
         .categoryHeader {
           margin-top: var(--spacing-l);
           margin-left: var(--spacing-l);
           text-transform: capitalize;
+          cursor: default;
         }
-        .categoryHeader iron-icon {
+        .categoryHeader .expandIcon {
+          width: var(--line-height-h3);
+          height: var(--line-height-h3);
+          margin-right: var(--spacing-s);
+        }
+        .categoryHeader .statusIcon {
           position: relative;
-          top: 1px;
+          top: 2px;
         }
-        .categoryHeader iron-icon.error {
+        .categoryHeader .statusIcon.error {
           color: var(--error-foreground);
         }
-        .categoryHeader iron-icon.warning {
+        .categoryHeader .statusIcon.warning {
           color: var(--warning-foreground);
         }
-        .categoryHeader iron-icon.info {
+        .categoryHeader .statusIcon.info {
           color: var(--info-foreground);
         }
-        .categoryHeader iron-icon.success {
+        .categoryHeader .statusIcon.success {
           color: var(--success-foreground);
         }
+        .collapsed table {
+          display: none;
+        }
+        .collapsed {
+          border-bottom: 1px solid var(--border-color);
+          padding-bottom: var(--spacing-m);
+        }
         .noCompleted {
           margin-top: var(--spacing-l);
         }
@@ -310,12 +366,30 @@
   render() {
     return html`
       <div><h2 class="heading-2">Results</h2></div>
-      ${this.renderNoCompleted()} ${this.renderSection(Category.ERROR)}
+      ${this.renderFilter()} ${this.renderNoCompleted()}
+      ${this.renderSection(Category.ERROR)}
       ${this.renderSection(Category.WARNING)}
-      ${this.renderSection(Category.INFO)} ${this.renderSuccess()}
+      ${this.renderSection(Category.INFO)} ${this.renderSection('SUCCESS')}
     `;
   }
 
+  renderFilter() {
+    if (this.runs.length === 0) return;
+    return html`
+      <input
+        id="filterInput"
+        type="text"
+        placeholder="Filter results by regular expression"
+        @input="${this.onInput}"
+      />
+    `;
+  }
+
+  onInput() {
+    assertIsDefined(this.filterInput, 'filter <input> element');
+    this.filterRegExp = new RegExp(this.filterInput.value, 'i');
+  }
+
   renderNoCompleted() {
     if (this.runs.some(hasCompleted)) return;
     let text = 'No results';
@@ -325,68 +399,76 @@
     return html`<div class="noCompleted">${text}</div>`;
   }
 
-  renderSection(category: Category) {
+  renderSection(category: Category | 'SUCCESS') {
     const catString = category.toString().toLowerCase();
-    const runs = this.runs.filter(r =>
-      (r.results ?? []).some(res => res.category === category)
-    );
+    let runs = this.runs;
+    if (category === 'SUCCESS') {
+      runs = runs
+        .filter(hasCompletedWithoutResults)
+        .filter(r => this.filterRegExp.test(r.checkName));
+    } else {
+      runs = runs.filter(r =>
+        (r.results ?? []).some(res => res.category === category)
+      );
+    }
     if (runs.length === 0) return;
+    const expanded = this.isSectionExpanded.get(category) ?? true;
+    const expandedClass = expanded ? 'expanded' : 'collapsed';
+    const icon = expanded ? 'gr-icons:expand-more' : 'gr-icons:expand-less';
     return html`
-      <h3 class="categoryHeader heading-3">
-        <iron-icon
-          icon="gr-icons:${iconForCategory(category)}"
-          class="${catString}"
-        ></iron-icon>
-        ${catString}
-      </h3>
-      <table class="resultsTable">
-        <thead>
-          <tr class="headerRow">
-            <th class="iconCol"></th>
-            <th class="nameCol">Run</th>
-            <th class="summaryCol">Summary</th>
-            <th class="expanderCol"></th>
-          </tr>
-        </thead>
-        <tbody>
-          ${runs.map(run => this.renderRun(category, run))}
-        </tbody>
-      </table>
+      <div class="${expandedClass}">
+        <h3
+          class="categoryHeader heading-3"
+          @click="${() => this.toggleExpanded(category)}"
+        >
+          <iron-icon class="expandIcon" icon="${icon}"></iron-icon>
+          <iron-icon
+            icon="gr-icons:${iconForCategory(category)}"
+            class="statusIcon ${catString}"
+          ></iron-icon>
+          ${catString}
+        </h3>
+        <table class="resultsTable">
+          <thead>
+            <tr class="headerRow">
+              <th class="iconCol"></th>
+              <th class="nameCol">Run</th>
+              <th class="summaryCol">Summary</th>
+              <th class="expanderCol"></th>
+            </tr>
+          </thead>
+          <tbody>
+            ${runs.map(run =>
+              category === 'SUCCESS'
+                ? this.renderSuccessfulRun(run)
+                : this.renderRun(category, run)
+            )}
+          </tbody>
+        </table>
+      </div>
     `;
   }
 
+  toggleExpanded(category: Category | 'SUCCESS') {
+    const expanded = this.isSectionExpanded.get(category) ?? true;
+    this.isSectionExpanded.set(category, !expanded);
+    this.requestUpdate();
+  }
+
   renderRun(category: Category, run: CheckRun) {
     return html`${run.results
       ?.filter(result => result.category === category)
+      .filter(
+        result =>
+          this.filterRegExp.test(run.checkName) ||
+          this.filterRegExp.test(result.summary)
+      )
       .map(
         result =>
           html`<gr-result-row .result="${{...run, ...result}}"></gr-result-row>`
       )}`;
   }
 
-  renderSuccess() {
-    const runs = this.runs.filter(hasCompletedWithoutResults);
-    if (runs.length === 0) return;
-    return html`
-      <h3 class="categoryHeader heading-3">
-        <iron-icon
-          icon="gr-icons:check-circle-outline"
-          class="success"
-        ></iron-icon>
-        Success
-      </h3>
-      <table class="resultsTable">
-        <tr class="headerRow">
-          <th class="iconCol"></th>
-          <th class="nameCol">Run</th>
-          <th class="summaryCol">Summary</th>
-          <th class="expanderCol"></th>
-        </tr>
-        ${runs.map(run => this.renderSuccessfulRun(run))}
-      </table>
-    `;
-  }
-
   renderSuccessfulRun(run: CheckRun) {
     const adaptedRun: RunResult = {
       category: Category.INFO, // will not be used, but is required
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
index 5b7428b..1b49f8a 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
@@ -16,7 +16,13 @@
  */
 import {html} from 'lit-html';
 import {classMap} from 'lit-html/directives/class-map';
-import {css, customElement, property} from 'lit-element';
+import {
+  css,
+  customElement,
+  internalProperty,
+  property,
+  query,
+} from 'lit-element';
 import {GrLitElement} from '../lit/gr-lit-element';
 import {Action, CheckRun, RunStatus} from '../../api/checks';
 import {sharedStyles} from '../../styles/shared-styles';
@@ -35,15 +41,14 @@
   fakeRun4,
   updateStateSetResults,
 } from '../../services/checks/checks-model';
+import {assertIsDefined} from '../../utils/common-util';
+import {whenVisible} from '../../utils/dom-util';
 
-/* The RunSelectedEvent is only used locally to communicate from <gr-checks-run>
-   to its <gr-checks-runs> parent. */
-
-interface RunSelectedEventDetail {
+export interface RunSelectedEventDetail {
   checkName: string;
 }
 
-type RunSelectedEvent = CustomEvent<RunSelectedEventDetail>;
+export type RunSelectedEvent = CustomEvent<RunSelectedEventDetail>;
 
 declare global {
   interface HTMLElementEventMap {
@@ -55,8 +60,8 @@
   target.dispatchEvent(
     new CustomEvent('run-selected', {
       detail: {checkName},
-      composed: false,
-      bubbles: false,
+      composed: true,
+      bubbles: true,
     })
   );
 }
@@ -106,6 +111,9 @@
         .chip.placeholder {
           border-left: var(--thick-border) solid var(--border-color);
         }
+        .chip.placeholder iron-icon {
+          display: none;
+        }
         .chip.error iron-icon {
           color: var(--error-foreground);
         }
@@ -124,9 +132,21 @@
           background-color: var(--selected-background);
           padding-left: calc(var(--spacing-m) + var(--thick-border) - 1px);
         }
+        div.chip.deselected {
+          border: 1px solid var(--gray-foreground);
+          background-color: transparent;
+          padding-left: calc(var(--spacing-m) + var(--thick-border) - 1px);
+        }
         div.chip.selected iron-icon {
           color: var(--selected-foreground);
         }
+        div.chip.deselected iron-icon {
+          color: var(--gray-foreground);
+        }
+        .chip.selected gr-button.action,
+        .chip.deselected gr-button.action {
+          display: none;
+        }
         gr-button.action {
           --padding: var(--spacing-xs) var(--spacing-m);
           /* The button should fit into the 20px line-height. The negative
@@ -139,15 +159,40 @@
     ];
   }
 
+  @query('.chip')
+  chipElement?: HTMLElement;
+
   @property()
   run!: CheckRun;
 
   @property()
   selected = false;
 
+  @property()
+  deselected = false;
+
+  @property()
+  shouldRender = false;
+
+  firstUpdated() {
+    assertIsDefined(this.chipElement, 'chip element');
+    whenVisible(
+      this.chipElement,
+      () => this.setAttribute('shouldRender', 'true'),
+      200
+    );
+  }
+
   render() {
-    const icon = this.selected ? 'check-circle' : iconForRun(this.run);
-    const classes = {chip: true, [icon]: true, selected: this.selected};
+    if (!this.shouldRender) return html`<div class="chip">Loading ...</div>`;
+
+    const icon = this.selected ? 'filter' : iconForRun(this.run);
+    const classes = {
+      chip: true,
+      [icon]: true,
+      selected: this.selected,
+      deselected: this.deselected,
+    };
     const action = primaryRunAction(this.run);
 
     return html`
@@ -185,10 +230,19 @@
 
 @customElement('gr-checks-runs')
 export class GrChecksRuns extends GrLitElement {
+  @query('#filterInput')
+  filterInput?: HTMLInputElement;
+
+  @internalProperty()
+  filterRegExp = new RegExp('');
+
   @property()
   runs: CheckRun[] = [];
 
-  private selectedRuns = new Set<string>();
+  @property()
+  selectedRuns: string[] = [];
+
+  private isSectionExpanded = new Map<RunStatus, boolean>();
 
   constructor() {
     super();
@@ -203,9 +257,29 @@
           display: block;
           padding: var(--spacing-xl);
         }
-        .statusHeader {
+        .expandIcon {
+          width: var(--line-height-h3);
+          height: var(--line-height-h3);
+        }
+        .sectionHeader {
           padding-top: var(--spacing-l);
           text-transform: capitalize;
+          cursor: default;
+        }
+        .sectionHeader h3 {
+          display: inline-block;
+        }
+        .collapsed .sectionRuns {
+          display: none;
+        }
+        .collapsed {
+          border-bottom: 1px solid var(--border-color);
+          padding-bottom: var(--spacing-m);
+        }
+        input#filterInput {
+          margin-top: var(--spacing-s);
+          padding: var(--spacing-s) var(--spacing-m);
+          width: 100%;
         }
         .testing {
           margin-top: var(--spacing-xxl);
@@ -227,6 +301,12 @@
   render() {
     return html`
       <h2 class="heading-2">Runs</h2>
+      <input
+        id="filterInput"
+        type="text"
+        placeholder="Filter runs by regular expression"
+        @input="${this.onInput}"
+      />
       ${this.renderSection(RunStatus.COMPLETED)}
       ${this.renderSection(RunStatus.RUNNING)}
       ${this.renderSection(RunStatus.RUNNABLE)}
@@ -253,6 +333,11 @@
     `;
   }
 
+  onInput() {
+    assertIsDefined(this.filterInput, 'filter <input> element');
+    this.filterRegExp = new RegExp(this.filterInput.value, 'i');
+  }
+
   none() {
     updateStateSetResults('f0', []);
     updateStateSetResults('f1', []);
@@ -277,34 +362,43 @@
   renderSection(status: RunStatus) {
     const runs = this.runs
       .filter(r => r.status === status)
+      .filter(r => this.filterRegExp.test(r.checkName))
       .sort(compareByWorstCategory);
     if (runs.length === 0) return;
+    const expanded = this.isSectionExpanded.get(status) ?? true;
+    const expandedClass = expanded ? 'expanded' : 'collapsed';
+    const icon = expanded ? 'gr-icons:expand-more' : 'gr-icons:expand-less';
     return html`
-      <div class="${status.toLowerCase()}">
-        <h3 class="statusHeader heading-3">${status.toLowerCase()}</h3>
-        ${runs.map(run => this.renderRun(run))}
+      <div class="${status.toLowerCase()} ${expandedClass}">
+        <div
+          class="sectionHeader"
+          @click="${() => this.toggleExpanded(status)}"
+        >
+          <iron-icon class="expandIcon" icon="${icon}"></iron-icon>
+          <h3 class="heading-3">${status.toLowerCase()}</h3>
+        </div>
+        <div class="sectionRuns">
+          ${runs.map(run => this.renderRun(run))}
+        </div>
       </div>
     `;
   }
 
+  toggleExpanded(status: RunStatus) {
+    const expanded = this.isSectionExpanded.get(status) ?? true;
+    this.isSectionExpanded.set(status, !expanded);
+    this.requestUpdate();
+  }
+
   renderRun(run: CheckRun) {
-    const selected = this.selectedRuns.has(run.checkName);
+    const selected = this.selectedRuns.includes(run.checkName);
+    const deselected = !selected && this.selectedRuns.length > 0;
     return html`<gr-checks-run
       .run="${run}"
       .selected="${selected}"
-      @run-selected="${this.handleRunSelected}"
+      .deselected="${deselected}"
     ></gr-checks-run>`;
   }
-
-  handleRunSelected(e: RunSelectedEvent) {
-    const checkName = e.detail.checkName;
-    if (this.selectedRuns.has(checkName)) {
-      this.selectedRuns.delete(checkName);
-    } else {
-      this.selectedRuns.add(checkName);
-    }
-    this.requestUpdate();
-  }
 }
 
 declare global {
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-tab.ts b/polygerrit-ui/app/elements/checks/gr-checks-tab.ts
index 61f8bd1..ad4f2ae 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-tab.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-tab.ts
@@ -15,7 +15,13 @@
  * limitations under the License.
  */
 import {html} from 'lit-html';
-import {css, customElement, property} from 'lit-element';
+import {
+  css,
+  customElement,
+  internalProperty,
+  property,
+  PropertyValues,
+} from 'lit-element';
 import {GrLitElement} from '../lit/gr-lit-element';
 import {Action, CheckResult, CheckRun} from '../../api/checks';
 import {
@@ -33,6 +39,8 @@
   fireActionTriggered,
 } from '../../services/checks/checks-util';
 import {checkRequiredProperty} from '../../utils/common-util';
+import {RunSelectedEvent} from './gr-checks-runs';
+import {ChecksTabState} from '../../types/events';
 
 /**
  * The "Checks" tab on the Gerrit change page. Gets its data from plugins that
@@ -48,11 +56,17 @@
   actions: Action[] = [];
 
   @property()
+  tabState?: ChecksTabState;
+
+  @property()
   currentPatchNum: PatchSetNum | undefined = undefined;
 
   @property()
   changeNum: NumericChangeId | undefined = undefined;
 
+  @internalProperty()
+  selectedRuns: string[] = [];
+
   constructor() {
     super();
     this.subscribe('runs', allRuns$);
@@ -100,6 +114,11 @@
 
   render() {
     const ps = `Patchset ${this.currentPatchNum} (Latest)`;
+    const filteredRuns = this.runs.filter(
+      r =>
+        this.selectedRuns.length === 0 ||
+        this.selectedRuns.includes(r.checkName)
+    );
     return html`
       <div class="header">
         <div class="left">
@@ -118,15 +137,30 @@
         </div>
       </div>
       <div class="container">
-        <gr-checks-runs class="runs" .runs="${this.runs}"></gr-checks-runs>
+        <gr-checks-runs
+          class="runs"
+          .runs="${this.runs}"
+          .selectedRuns="${this.selectedRuns}"
+          @run-selected="${this.handleRunSelected}"
+        ></gr-checks-runs>
         <gr-checks-results
           class="results"
-          .runs="${this.runs}"
+          .runs="${filteredRuns}"
         ></gr-checks-results>
       </div>
     `;
   }
 
+  protected updated(changedProperties: PropertyValues) {
+    super.updated(changedProperties);
+    if (changedProperties.has('tabState')) {
+      const check = this.tabState?.checkName;
+      if (check) {
+        this.selectedRuns = [check];
+      }
+    }
+  }
+
   renderAction(action: Action) {
     return html`<gr-checks-top-level-action
       .action="${action}"
@@ -148,6 +182,18 @@
       action.name
     );
   }
+
+  handleRunSelected(e: RunSelectedEvent) {
+    this.toggleSelected(e.detail.checkName);
+  }
+
+  toggleSelected(checkName: string) {
+    if (this.selectedRuns.includes(checkName)) {
+      this.selectedRuns = this.selectedRuns.filter(r => r !== checkName);
+    } else {
+      this.selectedRuns = [...this.selectedRuns, checkName];
+    }
+  }
 }
 
 @customElement('gr-checks-top-level-action')
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
index b43b3b0..bed07a6 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
@@ -304,7 +304,7 @@
         if (!config) {
           throw new Error('getConfig returned undefined');
         }
-        this._retreiveFeedbackURL(config);
+        this._retrieveFeedbackURL(config);
         this._retrieveRegisterURL(config);
         return getDocsBaseUrl(config, this.restApiService);
       })
@@ -325,7 +325,7 @@
     });
   }
 
-  _retreiveFeedbackURL(config: ServerInfo) {
+  _retrieveFeedbackURL(config: ServerInfo) {
     if (config.gerrit?.report_bug_url) {
       this._feedbackURL = config.gerrit.report_bug_url;
     }
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
index 7430cc0..d9c43d6 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
@@ -488,7 +488,7 @@
         report_bug_url: url,
       },
     };
-    element._retreiveFeedbackURL(config);
+    element._retrieveFeedbackURL(config);
     await flush();
 
     assert.equal(element._feedbackURL, url);
diff --git a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
index f2ee838..632ce4c 100644
--- a/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
+++ b/polygerrit-ui/app/elements/core/gr-navigation/gr-navigation.ts
@@ -249,7 +249,7 @@
 
 export interface GenerateUrlChangeViewParameters {
   view: GerritView.CHANGE;
-  // TODO(TS): NumericChangeId - not sure about it, may be it can be removeds
+  // TODO(TS): NumericChangeId - not sure about it, may be it can be removed
   changeNum: NumericChangeId;
   project: RepoName;
   patchNum?: PatchSetNum;
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
index 43f8a2b..97d5271 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
@@ -93,6 +93,7 @@
   'onlyextensions:',
   'owner:',
   'ownerin:',
+  'parentof:',
   'parentproject:',
   'project:',
   'projects:',
diff --git a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
index 19f43c2..b60a585 100644
--- a/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
+++ b/polygerrit-ui/app/elements/diff/gr-comment-api/gr-comment-api.ts
@@ -611,7 +611,7 @@
 
   private readonly flagsService = appContext.flagsService;
 
-  private _isPortingCommentsExperimentEnabled = false;
+  private isPortingCommentsExperimentEnabled = false;
 
   /** @override */
   created() {
@@ -620,7 +620,7 @@
 
   constructor() {
     super();
-    this._isPortingCommentsExperimentEnabled = this.flagsService.isEnabled(
+    this.isPortingCommentsExperimentEnabled = this.flagsService.isEnabled(
       KnownExperimentId.PORTING_COMMENTS
     );
   }
@@ -636,10 +636,10 @@
       this.restApiService.getDiffComments(changeNum),
       this.restApiService.getDiffRobotComments(changeNum),
       this.restApiService.getDiffDrafts(changeNum),
-      this._isPortingCommentsExperimentEnabled
+      this.isPortingCommentsExperimentEnabled
         ? this.restApiService.getPortedComments(changeNum, revision)
         : Promise.resolve({}),
-      this._isPortingCommentsExperimentEnabled
+      this.isPortingCommentsExperimentEnabled
         ? this.restApiService.getPortedDrafts(changeNum, revision)
         : Promise.resolve({}),
     ];
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
index da1b928..4943298 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.ts
@@ -33,7 +33,7 @@
 
 /**
  * In JS, unicode code points above 0xFFFF occupy two elements of a string.
- * For example '𐀏'.length is 2. An occurence of such a code point is called a
+ * For example '𐀏'.length is 2. An occurrence of such a code point is called a
  * surrogate pair.
  *
  * This regex segments a string along tabs ('\t') and surrogate pairs, since
@@ -80,7 +80,7 @@
 
   readonly groups: GrDiffGroup[];
 
-  private _blameInfo: BlameInfo[] | null;
+  private blameInfo: BlameInfo[] | null;
 
   private readonly _layerUpdateListener: (
     start: LineNumber,
@@ -104,7 +104,7 @@
     this._prefs = prefs;
     this._outputEl = outputEl;
     this.groups = [];
-    this._blameInfo = null;
+    this.blameInfo = null;
 
     if (isNaN(prefs.tab_size) || prefs.tab_size <= 0) {
       throw Error('Invalid tab size from preferences.');
@@ -765,7 +765,7 @@
    * re-render its blame cell content.
    */
   setBlame(blame: BlameInfo[] | null) {
-    this._blameInfo = blame;
+    this.blameInfo = blame;
     if (!blame) return;
 
     // TODO(wyatta): make this loop asynchronous.
@@ -890,11 +890,11 @@
    * @return The commit information.
    */
   _getBlameCommitForBaseLine(lineNum: LineNumber) {
-    if (!this._blameInfo) {
+    if (!this.blameInfo) {
       return null;
     }
 
-    for (const blameCommit of this._blameInfo) {
+    for (const blameCommit of this.blameInfo) {
       for (const range of blameCommit.ranges) {
         if (range.start <= lineNum && range.end >= lineNum) {
           return blameCommit;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
index 5ac37dc..cc3be07 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
@@ -61,7 +61,7 @@
     return htmlTemplate;
   }
 
-  private _preventAutoScrollOnManualScroll = false;
+  private preventAutoScrollOnManualScroll = false;
 
   private lastDisplayedNavigateToNextFileToast: number | null = null;
 
@@ -338,10 +338,10 @@
   }
 
   private _boundHandleWindowScroll = () => {
-    if (this._preventAutoScrollOnManualScroll) {
+    if (this.preventAutoScrollOnManualScroll) {
       this._scrollMode = ScrollMode.NEVER;
       this._focusOnMove = false;
-      this._preventAutoScrollOnManualScroll = false;
+      this.preventAutoScrollOnManualScroll = false;
     }
   };
 
@@ -360,14 +360,14 @@
   };
 
   private _boundHandleDiffRenderStart = () => {
-    this._preventAutoScrollOnManualScroll = true;
+    this.preventAutoScrollOnManualScroll = true;
   };
 
   private _boundHandleDiffRenderContent = () => {
     this._updateStops();
     // When done rendering, turn focus on move and automatic scrolling back on
     this._focusOnMove = true;
-    this._preventAutoScrollOnManualScroll = false;
+    this.preventAutoScrollOnManualScroll = false;
   };
 
   private _boundHandleDiffLineSelected = (event: Event) => {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-overview-image.ts b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-overview-image.ts
new file mode 100644
index 0000000..42268e9
--- /dev/null
+++ b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-overview-image.ts
@@ -0,0 +1,304 @@
+/**
+ * @license
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  css,
+  customElement,
+  html,
+  internalProperty,
+  LitElement,
+  property,
+  PropertyValues,
+  query,
+} from 'lit-element';
+import {StyleInfo, styleMap} from 'lit-html/directives/style-map';
+
+import {Dimensions, fitToFrame, Point, Rect} from './util';
+
+/**
+ * Displays a scaled-down version of an image with a draggable frame for
+ * choosing a portion of the image to be magnified by other components.
+ *
+ * Slotted content can be arbitrary elements, but should be limited to images or
+ * stacks of image-like elements (e.g. for overlays) with limited interactivity,
+ * to prevent confusion, as the component only captures a limited set of events.
+ * Slotted content is scaled to fit the bounds of the component, with
+ * letterboxing if aspect ratios differ. For slotted content smaller than the
+ * component, it will cap the scale at 1x and also apply letterboxing.
+ */
+@customElement('gr-overview-image')
+export class GrOverviewImage extends LitElement {
+  @property({type: Object})
+  frameRect: Rect = {origin: {x: 0, y: 0}, dimensions: {width: 0, height: 0}};
+
+  @internalProperty() protected contentStyle: StyleInfo = {};
+
+  @internalProperty() protected contentTransformStyle: StyleInfo = {};
+
+  @internalProperty() protected frameStyle: StyleInfo = {};
+
+  @internalProperty() protected overlayStyle: StyleInfo = {};
+
+  @internalProperty() protected dragging = false;
+
+  @query('.content-box') protected contentBox!: HTMLDivElement;
+
+  @query('.content') protected content!: HTMLDivElement;
+
+  @query('.content-transform') protected contentTransform!: HTMLDivElement;
+
+  @query('.frame') protected frame!: HTMLDivElement;
+
+  private contentBounds: Dimensions = {width: 0, height: 0};
+
+  private imageBounds: Dimensions = {width: 0, height: 0};
+
+  private scale = 1;
+
+  // When grabbing the frame to drag it around, this stores the offset of the
+  // cursor from the center of the frame at the start of the drag.
+  private grabOffset: Point = {x: 0, y: 0};
+
+  private readonly resizeObserver = new ResizeObserver(
+    (entries: ResizeObserverEntry[]) => {
+      for (const entry of entries) {
+        if (entry.target === this.contentBox) {
+          this.contentBounds = {
+            width: entry.contentRect.width,
+            height: entry.contentRect.height,
+          };
+        }
+        if (entry.target === this.contentTransform) {
+          this.imageBounds = {
+            width: entry.contentRect.width,
+            height: entry.contentRect.height,
+          };
+        }
+        this.updateScale();
+      }
+    }
+  );
+
+  static styles = css`
+    :host {
+      --overview-image-background-color: #000;
+      --overview-image-frame-color: #f00;
+      display: flex;
+    }
+    * {
+      box-sizing: border-box;
+    }
+    ::slotted(*) {
+      display: block;
+    }
+    .content-box {
+      border: 1px solid var(--overview-image-background-color);
+      background-color: var(--overview-iamge-background-color);
+      width: 100%;
+      position: relative;
+    }
+    .content {
+      position: absolute;
+      cursor: pointer;
+    }
+    .content-transform {
+      position: absolute;
+      transform-origin: top left;
+      will-change: transform;
+    }
+    .frame {
+      border: 1px solid var(--overview-image-frame-color);
+      position: absolute;
+      will-change: transform;
+    }
+    .overlay {
+      position: absolute;
+      z-index: 10000;
+      cursor: grabbing;
+    }
+  `;
+
+  render() {
+    return html`
+      <div class="content-box">
+        <div
+          class="content"
+          style="${styleMap({
+            ...this.contentStyle,
+          })}"
+          @mousemove="${this.maybeDragFrame}"
+          @mousedown=${this.clickOverview}
+          @mouseup="${this.releaseFrame}"
+        >
+          <div
+            class="content-transform"
+            style="${styleMap(this.contentTransformStyle)}"
+          >
+            <slot></slot>
+          </div>
+          <div
+            class="frame"
+            style="${styleMap({
+              ...this.frameStyle,
+              cursor: this.dragging ? 'grabbing' : 'grab',
+            })}"
+            @mousedown="${this.grabFrame}"
+          ></div>
+        </div>
+        <div
+          class="overlay"
+          style="${styleMap({
+            ...this.overlayStyle,
+            display: this.dragging ? 'block' : 'none',
+          })}"
+          @mousemove="${this.overlayMouseMove}"
+          @mouseleave="${this.releaseFrame}"
+          @mouseup="${this.releaseFrame}"
+        ></div>
+      </div>
+    `;
+  }
+
+  firstUpdated() {
+    this.resizeObserver.observe(this.contentBox);
+    this.resizeObserver.observe(this.contentTransform);
+  }
+
+  updated(changedProperties: PropertyValues) {
+    if (changedProperties.has('frameRect')) {
+      this.updateFrameStyle();
+    }
+  }
+
+  clickOverview(event: MouseEvent) {
+    event.preventDefault();
+
+    this.updateOverlaySize();
+
+    this.dragging = true;
+    const rect = this.content.getBoundingClientRect();
+    this.notifyNewCenter({
+      x: (event.clientX - rect.left) / this.scale,
+      y: (event.clientY - rect.top) / this.scale,
+    });
+  }
+
+  grabFrame(event: MouseEvent) {
+    event.preventDefault();
+    // Do not bubble up into clickOverview().
+    event.stopPropagation();
+
+    this.updateOverlaySize();
+
+    this.dragging = true;
+    const rect = this.frame.getBoundingClientRect();
+    const frameCenterX = rect.x + rect.width / 2;
+    const frameCenterY = rect.y + rect.height / 2;
+    this.grabOffset = {
+      x: event.clientX - frameCenterX,
+      y: event.clientY - frameCenterY,
+    };
+  }
+
+  maybeDragFrame(event: MouseEvent) {
+    event.preventDefault();
+    if (!this.dragging) return;
+    const rect = this.content.getBoundingClientRect();
+    const center = {
+      x: (event.clientX - rect.left - this.grabOffset.x) / this.scale,
+      y: (event.clientY - rect.top - this.grabOffset.y) / this.scale,
+    };
+    this.notifyNewCenter(center);
+  }
+
+  releaseFrame(event: MouseEvent) {
+    event.preventDefault();
+    this.dragging = false;
+    this.grabOffset = {x: 0, y: 0};
+  }
+
+  overlayMouseMove(event: MouseEvent) {
+    event.preventDefault();
+    this.maybeDragFrame(event);
+  }
+
+  private updateScale() {
+    const fitted = fitToFrame(this.imageBounds, this.contentBounds);
+    this.scale = fitted.scale;
+
+    this.contentStyle = {
+      ...this.contentStyle,
+      top: `${fitted.top}px`,
+      left: `${fitted.left}px`,
+      width: `${fitted.width}px`,
+      height: `${fitted.height}px`,
+    };
+
+    this.contentTransformStyle = {
+      transform: `scale(${this.scale})`,
+    };
+
+    this.updateFrameStyle();
+  }
+
+  private updateFrameStyle() {
+    const x = this.frameRect.origin.x * this.scale;
+    const y = this.frameRect.origin.y * this.scale;
+    const width = this.frameRect.dimensions.width * this.scale;
+    const height = this.frameRect.dimensions.height * this.scale;
+    this.frameStyle = {
+      ...this.frameStyle,
+      transform: `translate(${x}px, ${y}px)`,
+      width: `${width}px`,
+      height: `${height}px`,
+    };
+  }
+
+  private updateOverlaySize() {
+    const rect = this.contentBox.getBoundingClientRect();
+    // Create a whole-page overlay to capture mouse events, so that the drag
+    // interaction continues until the user releases the mouse button. Since
+    // innerWidth and innerHeight include scrollbars, we subtract 20 pixels each
+    // to prevent the overlay from extending offscreen under any existing
+    // scrollbar and causing the scrollbar for the other dimension to show up
+    // unnecessarily.
+    const width = window.innerWidth - 20;
+    const height = window.innerHeight - 20;
+    this.overlayStyle = {
+      ...this.overlayStyle,
+      top: `-${rect.top + 1}px`,
+      left: `-${rect.left + 1}px`,
+      width: `${width}px`,
+      height: `${height}px`,
+    };
+  }
+
+  private notifyNewCenter(center: Point) {
+    this.dispatchEvent(
+      new CustomEvent('center-updated', {
+        detail: {...center},
+        bubbles: true,
+        composed: true,
+      })
+    );
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'gr-overview-image': GrOverviewImage;
+  }
+}
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-zoomed-image.ts b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-zoomed-image.ts
new file mode 100644
index 0000000..a14a9cc
--- /dev/null
+++ b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-zoomed-image.ts
@@ -0,0 +1,95 @@
+/**
+ * @license
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  css,
+  customElement,
+  html,
+  internalProperty,
+  LitElement,
+  property,
+  PropertyValues,
+} from 'lit-element';
+import {StyleInfo, styleMap} from 'lit-html/directives/style-map';
+import {Rect} from './util';
+
+/**
+ * Displays its slotted content at a given scale, centered over a given point,
+ * while ensuring the content always fills the container. The content does not
+ * have to be a single image, it can be arbitrary HTML. To prevent user
+ * confusion, it should ideally be image-like, i.e. have limited or no
+ * interactivity, as the component does not prevent events or focus from
+ * reaching the slotted content.
+ */
+@customElement('gr-zoomed-image')
+export class GrZoomedImage extends LitElement {
+  @property({type: Number}) scale = 1;
+
+  @property({type: Object})
+  frameRect: Rect = {origin: {x: 0, y: 0}, dimensions: {width: 0, height: 0}};
+
+  @internalProperty() protected imageStyles: StyleInfo = {};
+
+  static styles = css`
+    :host {
+      display: block;
+    }
+    ::slotted(*) {
+      display: block;
+    }
+    #clip {
+      position: relative;
+      width: 100%;
+      height: 100%;
+      overflow: hidden;
+    }
+    #transform {
+      position: absolute;
+      transform-origin: top left;
+      will-change: transform;
+    }
+  `;
+
+  render() {
+    return html`
+      <div id="clip">
+        <div id="transform" style="${styleMap(this.imageStyles)}">
+          <slot></slot>
+        </div>
+      </div>
+    `;
+  }
+
+  updated(changedProperties: PropertyValues) {
+    if (changedProperties.has('scale') || changedProperties.has('frameRect')) {
+      this.updateImageStyles();
+    }
+  }
+
+  private updateImageStyles() {
+    const {x, y} = this.frameRect.origin;
+    this.imageStyles = {
+      'image-rendering': this.scale >= 1 ? 'pixelated' : 'auto',
+      transform: `translate(${-x}px, ${-y}px) scale(${this.scale})`,
+    };
+  }
+}
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'gr-zoomed-image': GrZoomedImage;
+  }
+}
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util.ts b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util.ts
new file mode 100644
index 0000000..b42eea9
--- /dev/null
+++ b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util.ts
@@ -0,0 +1,236 @@
+/**
+ * @license
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export interface Point {
+  x: number;
+  y: number;
+}
+
+export interface Dimensions {
+  width: number;
+  height: number;
+}
+
+export interface Rect {
+  origin: Point;
+  dimensions: Dimensions;
+}
+
+export interface FittedContent {
+  top: number;
+  left: number;
+  width: number;
+  height: number;
+  scale: number;
+}
+
+function clamp(value: number, min: number, max: number) {
+  return Math.max(min, Math.min(value, max));
+}
+
+/**
+ * Fits content of the given dimensions into the given frame, maintaining the
+ * aspect ratio of the content and applying letterboxing / pillarboxing as
+ * needed.
+ */
+export function fitToFrame(
+  content: Dimensions,
+  frame: Dimensions
+): FittedContent {
+  const contentAspectRatio = content.width / content.height;
+  const frameAspectRatio = frame.width / frame.height;
+  // If the content is wider than the frame, it will be letterboxed, otherwise
+  // it will be pillarboxed. When letterboxed, content and frame width will
+  // match exactly, when pillarboxed, content and frame height will match
+  // exactly.
+  const isLetterboxed = contentAspectRatio > frameAspectRatio;
+  let width: number;
+  let height: number;
+  if (isLetterboxed) {
+    width = Math.min(frame.width, content.width);
+    height = content.height * (width / content.width);
+  } else {
+    height = Math.min(frame.height, content.height);
+    width = content.width * (height / content.height);
+  }
+  const top = (frame.height - height) / 2;
+  const left = (frame.width - width) / 2;
+  const scale = width / content.width;
+  return {top, left, width, height, scale};
+}
+
+function ensureInBounds(part: Rect, bounds: Dimensions): Rect {
+  const x =
+    part.dimensions.width <= bounds.width
+      ? clamp(part.origin.x, 0, bounds.width - part.dimensions.width)
+      : (bounds.width - part.dimensions.width) / 2;
+  const y =
+    part.dimensions.height <= bounds.height
+      ? clamp(part.origin.y, 0, bounds.height - part.dimensions.height)
+      : (bounds.height - part.dimensions.height) / 2;
+  return {origin: {x, y}, dimensions: part.dimensions};
+}
+
+/**
+ * Maintains a given frame inside given bounds, adjusting requested positions
+ * for the frame as needed. This supports the non-destructive application of a
+ * scaling factor, so that e.g. the magnification of an image can be changed
+ * easily while keeping the frame centered over the same spot. Changing bounds
+ * or frame size also keeps the frame position when possible.
+ */
+export class FrameConstrainer {
+  private center: Point = {x: 0, y: 0};
+
+  private frameSize: Dimensions = {width: 0, height: 0};
+
+  private bounds: Dimensions = {width: 0, height: 0};
+
+  private scale = 1;
+
+  private unscaledFrame: Rect = {
+    origin: {x: 0, y: 0},
+    dimensions: {width: 0, height: 0},
+  };
+
+  private scaledFrame: Rect = {
+    origin: {x: 0, y: 0},
+    dimensions: {width: 0, height: 0},
+  };
+
+  getCenter(): Point {
+    return {...this.center};
+  }
+
+  /**
+   * Returns the frame at its original size, positioned within the given bounds
+   * at the given scale; its origin will be in scaled bounds coordinates.
+   *
+   * Ex: for given bounds 100x50 and frame size 30x20, centered over (50, 25),
+   * all at 1x scale, when setting scale to 2, this will return a frame of size
+   * 30x20, centered over (100, 50), within bounds 200x100.
+   *
+   * Useful for positioning a viewport of fixed size over a magnified image.
+   */
+  getUnscaledFrame(): Rect {
+    return {
+      origin: {...this.unscaledFrame.origin},
+      dimensions: {...this.unscaledFrame.dimensions},
+    };
+  }
+
+  /**
+   * Returns the scaled down frame–a scale of 2 will result in frame dimensions
+   * being halved—position within the given bounds at 1x scale; its origin will
+   * be in unscaled bounds coordinates.
+   *
+   * Ex: for given bounds 100x50 and frame size 30x20, centered over (50, 25),
+   * all at 1x scale, when setting scale to 2, this will return a frame of size
+   * 15x10, centered over (50, 25), within bounds 100x50.
+   *
+   * Useful for highlighting the magnified portion of an image as determined by
+   * getUnscaledFrame() in an overview image of fixed size.
+   */
+  getScaledFrame(): Rect {
+    return {
+      origin: {...this.scaledFrame.origin},
+      dimensions: {...this.scaledFrame.dimensions},
+    };
+  }
+
+  /**
+   * Requests the frame to be centered over the given point, in unscaled bounds
+   * coordinates. This will keep the frame within the given bounds, also when
+   * requesting a center point fully outside the given bounds.
+   */
+  requestCenter(center: Point) {
+    this.center = {...center};
+
+    this.ensureFrameInBounds();
+  }
+
+  /**
+   * Sets the frame size, while keeping the frame within the given bounds, and
+   * maintaining the current center if possible.
+   */
+  setFrameSize(frameSize: Dimensions) {
+    if (frameSize.width <= 0 || frameSize.height <= 0) return;
+    this.frameSize = {...frameSize};
+
+    this.ensureFrameInBounds();
+  }
+
+  /**
+   * Sets the bounds, while keeping the frame within them, and maintaining the
+   * current center if possible.
+   */
+  setBounds(bounds: Dimensions) {
+    if (bounds.width <= 0 || bounds.height <= 0) return;
+    this.bounds = {...bounds};
+
+    this.ensureFrameInBounds();
+  }
+
+  /**
+   * Sets the applied scale, while keeping the frame within the given bounds,
+   * and maintaining the current center if possible (both relevant moving from
+   * a larger scale to a smaller scale).
+   */
+  setScale(scale: number) {
+    if (!scale || scale <= 0) return;
+    this.scale = scale;
+
+    this.ensureFrameInBounds();
+  }
+
+  private ensureFrameInBounds() {
+    const scaledCenter = {
+      x: this.center.x * this.scale,
+      y: this.center.y * this.scale,
+    };
+    const scaledBounds = {
+      width: this.bounds.width * this.scale,
+      height: this.bounds.height * this.scale,
+    };
+    const scaledFrameSize = {
+      width: this.frameSize.width / this.scale,
+      height: this.frameSize.height / this.scale,
+    };
+
+    const requestedUnscaledFrame = {
+      origin: {
+        x: scaledCenter.x - this.frameSize.width / 2,
+        y: scaledCenter.y - this.frameSize.height / 2,
+      },
+      dimensions: this.frameSize,
+    };
+    const requestedScaledFrame = {
+      origin: {
+        x: this.center.x - scaledFrameSize.width / 2,
+        y: this.center.y - scaledFrameSize.height / 2,
+      },
+      dimensions: scaledFrameSize,
+    };
+
+    this.unscaledFrame = ensureInBounds(requestedUnscaledFrame, scaledBounds);
+    this.scaledFrame = ensureInBounds(requestedScaledFrame, this.bounds);
+
+    this.center = {
+      x: this.scaledFrame.origin.x + this.scaledFrame.dimensions.width / 2,
+      y: this.scaledFrame.origin.y + this.scaledFrame.dimensions.height / 2,
+    };
+  }
+}
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util_test.js b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util_test.js
new file mode 100644
index 0000000..80cfa36
--- /dev/null
+++ b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/util_test.js
@@ -0,0 +1,171 @@
+/**
+ * @license
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import '../../../test/common-test-setup-karma.js';
+import {FrameConstrainer} from './util.js';
+
+suite('FrameConstrainer tests', () => {
+  let constrainer;
+
+  setup(() => {
+    constrainer = new FrameConstrainer();
+    constrainer.setBounds({width: 100, height: 100});
+    constrainer.setFrameSize({width: 50, height: 50});
+    constrainer.requestCenter({x: 50, y: 50});
+  });
+
+  suite('changing center', () => {
+    test('moves frame to requested position', () => {
+      constrainer.requestCenter({x: 30, y: 30});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 5, y: 5}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('keeps frame in bounds for top left corner', () => {
+      constrainer.requestCenter({x: 5, y: 5});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 0, y: 0}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('keeps frame in bounds for bottom right corner', () => {
+      constrainer.requestCenter({x: 95, y: 95});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 50, y: 50}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('handles out-of-bounds center left', () => {
+      constrainer.requestCenter({x: -5, y: 50});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 0, y: 25}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('handles out-of-bounds center right', () => {
+      constrainer.requestCenter({x: 105, y: 50});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 50, y: 25}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('handles out-of-bounds center top', () => {
+      constrainer.requestCenter({x: 50, y: -5});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 25, y: 0}, dimensions: {width: 50, height: 50}});
+    });
+
+    test('handles out-of-bounds center bottom', () => {
+      constrainer.requestCenter({x: 50, y: 105});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 25, y: 50}, dimensions: {width: 50, height: 50}});
+    });
+  });
+
+  suite('changing frame size', () => {
+    test('maintains center when decreased', () => {
+      constrainer.setFrameSize({width: 10, height: 10});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 45, y: 45}, dimensions: {width: 10, height: 10}});
+    });
+
+    test('maintains center when increased', () => {
+      constrainer.setFrameSize({width: 80, height: 80});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 10, y: 10}, dimensions: {width: 80, height: 80}});
+    });
+
+    test('updates center to remain in bounds when increased', () => {
+      constrainer.setFrameSize({width: 10, height: 10});
+      constrainer.requestCenter({x: 95, y: 95});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 90, y: 90}, dimensions: {width: 10, height: 10}});
+
+      constrainer.setFrameSize({width: 20, height: 20});
+      assert.deepEqual(
+          constrainer.getUnscaledFrame(),
+          {origin: {x: 80, y: 80}, dimensions: {width: 20, height: 20}});
+    });
+  });
+
+  suite('changing scale', () => {
+    suite('for unscaled frame', () => {
+      test('adjusts origin to maintain center when zooming in', () => {
+        constrainer.setScale(2);
+        assert.deepEqual(
+            constrainer.getUnscaledFrame(),
+            {origin: {x: 75, y: 75}, dimensions: {width: 50, height: 50}});
+      });
+
+      test('adjusts origin to maintain center when zooming out', () => {
+        constrainer.setFrameSize({width: 20, height: 20});
+        constrainer.setScale(0.5);
+        assert.deepEqual(
+            constrainer.getUnscaledFrame(),
+            {origin: {x: 15, y: 15}, dimensions: {width: 20, height: 20}});
+      });
+
+      test('keeps frame in bounds when zooming out', () => {
+        constrainer.setScale(5);
+        constrainer.requestCenter({x: 100, y: 100});
+        assert.deepEqual(
+            constrainer.getUnscaledFrame(),
+            {origin: {x: 450, y: 450}, dimensions: {width: 50, height: 50}});
+
+        constrainer.setScale(1);
+        assert.deepEqual(
+            constrainer.getUnscaledFrame(),
+            {origin: {x: 50, y: 50}, dimensions: {width: 50, height: 50}});
+      });
+    });
+
+    suite('for scaled frame', () => {
+      test('decreases frame size and maintains center when zooming in', () => {
+        constrainer.setScale(2);
+        assert.deepEqual(
+            constrainer.getScaledFrame(),
+            {origin: {x: 37.5, y: 37.5}, dimensions: {width: 25, height: 25}});
+      });
+
+      test('increases frame size and maintains center when zooming out', () => {
+        constrainer.setFrameSize({width: 20, height: 20});
+        constrainer.setScale(0.5);
+        assert.deepEqual(
+            constrainer.getScaledFrame(),
+            {origin: {x: 30, y: 30}, dimensions: {width: 40, height: 40}});
+      });
+
+      test('keeps frame in bounds when zooming out', () => {
+        constrainer.setScale(5);
+        constrainer.requestCenter({x: 100, y: 100});
+        assert.deepEqual(
+            constrainer.getScaledFrame(),
+            {origin: {x: 90, y: 90}, dimensions: {width: 10, height: 10}});
+
+        constrainer.setScale(1);
+        assert.deepEqual(
+            constrainer.getScaledFrame(),
+            {origin: {x: 50, y: 50}, dimensions: {width: 50, height: 50}});
+      });
+    });
+  });
+});
\ No newline at end of file
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
index cfe2cfe..60f2853 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector.ts
@@ -60,17 +60,17 @@
       this.restApiService.savePreferences({diff_view: newMode});
     }
     this.mode = newMode;
-    let annoucement;
+    let announcement;
     if (this.isUnifiedSelected(newMode)) {
-      annoucement = 'Changed diff view to unified';
+      announcement = 'Changed diff view to unified';
     } else if (this.isSideBySideSelected(newMode)) {
-      annoucement = 'Changed diff view to side by side';
+      announcement = 'Changed diff view to side by side';
     }
-    if (annoucement) {
+    if (announcement) {
       this.fire(
         'iron-announce',
         {
-          text: annoucement,
+          text: announcement,
         },
         {bubbles: true}
       );
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
index 088d9cf..2c4b8f6 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
@@ -1465,9 +1465,9 @@
   ) {
     let patchNum = patchRange.patchNum;
 
-    const comparedAgainsParent = patchRange.basePatchNum === 'PARENT';
+    const comparedAgainstParent = patchRange.basePatchNum === 'PARENT';
 
-    if (isBase && !comparedAgainsParent) {
+    if (isBase && !comparedAgainstParent) {
       patchNum = patchRange.basePatchNum;
     }
 
@@ -1475,7 +1475,7 @@
       changeBaseURL(project, changeNum, patchNum) +
       `/files/${encodeURIComponent(path)}/download`;
 
-    if (isBase && comparedAgainsParent) {
+    if (isBase && comparedAgainstParent) {
       url += '?parent=1';
     }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
index 5edd353..0ca929a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff-utils.ts
@@ -40,7 +40,7 @@
 }
 
 export function isLongCommentRange(range: CommentRange): boolean {
-  return range.end_line - range.start_line > 5;
+  return range.end_line - range.start_line > 10;
 }
 
 export function getLineNumber(lineEl?: Element | null): LineNumber | null {
@@ -88,7 +88,7 @@
 // TODO: This type should be exposed to gr-diff clients in a separate type file.
 // For Gerrit these are instances of GrCommentThread, but other gr-diff users
 // have different HTML elements in use for comment threads.
-// TODO: Also document the required HTML attritbutes that thread elements must
+// TODO: Also document the required HTML attributes that thread elements must
 // have, e.g. 'diff-side', 'range', 'line-num', 'data-value'.
 export interface GrDiffThreadElement extends HTMLElement {
   rootId: string;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
index 6fef223..49eac72 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_test.js
@@ -558,7 +558,7 @@
     test('adds long range comment chip', async () => {
       const range = {
         start_line: 1,
-        end_line: 7,
+        end_line: 12,
         start_character: 0,
         end_character: 0,
       };
@@ -572,7 +572,7 @@
         a: [],
         b: [],
       }, {
-        ab: Array(8).fill('text'),
+        ab: Array(13).fill('text'),
       }];
       setupSampleDiff({content});
 
@@ -586,7 +586,7 @@
     test('no duplicate range chip for same thread', async () => {
       const range = {
         start_line: 1,
-        end_line: 7,
+        end_line: 12,
         start_character: 0,
         end_character: 0,
       };
@@ -604,7 +604,7 @@
         a: [],
         b: [],
       }, {
-        ab: Array(8).fill('text'),
+        ab: Array(13).fill('text'),
       }];
       setupSampleDiff({content});
 
diff --git a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_html.ts b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_html.ts
index 52465b3..5ab8449 100644
--- a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select_html.ts
@@ -35,7 +35,6 @@
         text-transform: none;
         font-family: var(--font-family);
       }
-      --trigger-hover-color: rgba(0, 0, 0, 0.6);
     }
     @media screen and (max-width: 50em) {
       .filesWeblinks {
diff --git a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.js b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.js
index fad717d..8279ab1 100644
--- a/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-ranged-comment-layer/gr-ranged-comment-layer_test.js
@@ -72,7 +72,7 @@
         side: 'right',
         range: {
           end_character: 1,
-          end_line: 70,
+          end_line: 71,
           start_character: 1,
           start_line: 60,
         },
@@ -314,10 +314,10 @@
     assert.equal(element._rangesMap.left[39][0].start, 0);
     assert.equal(element._rangesMap.left[39][0].end, 9);
 
-    // The right has four ranged comments: 10-12, 55-55, 60-70, 100-100
+    // The right has four ranged comments: 10-12, 55-55, 60-71, 100-100
     const rightKeys = [];
     for (let i = 10; i <= 12; i++) { rightKeys.push('' + i); }
-    for (let i = 60; i <= 70; i++) { rightKeys.push('' + i); }
+    for (let i = 60; i <= 71; i++) { rightKeys.push('' + i); }
     rightKeys.push('55', '100');
     assert.deepEqual(Object.keys(element._rangesMap.right).sort(),
         rightKeys.sort());
diff --git a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
index da29b85..1150674 100644
--- a/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
+++ b/polygerrit-ui/app/elements/diff/gr-syntax-layer/gr-syntax-layer.ts
@@ -492,7 +492,7 @@
    * with code it shouldn't AND to avoid executing regexes as much as
    * possible.
    * * These tests should document the issue clearly enough that the test can
-   * be condidently removed when the issue is solved in HLJS.
+   * be confidently removed when the issue is solved in HLJS.
    * * These tests should rewrite the line of code to have the same number of
    * characters. This method rewrites the string that gets parsed, but NOT
    * the string that gets displayed and highlighted. Thus, the positions
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
index b36edd4..bc153ee 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
@@ -277,7 +277,8 @@
     return this.restApiService
       .queryChangeFiles(this.change._number, this.patchNum, input)
       .then(res => {
-        if (!res) throw new Error('Failed to retrieve files. Reponse not set.');
+        if (!res)
+          throw new Error('Failed to retrieve files. Response not set.');
         return res.map(file => {
           return {name: file};
         });
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
index be6ffc4..bbf4790 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.js
@@ -50,14 +50,14 @@
 
   suite('edit button CUJ', () => {
     let navStubs;
-    let openAutoCcmplete;
+    let openAutoComplete;
 
     setup(() => {
       navStubs = [
         sinon.stub(GerritNav, 'getEditUrlForDiff'),
         sinon.stub(GerritNav, 'navigateToRelativeUrl'),
       ];
-      openAutoCcmplete = element.$.openDialog.querySelector('gr-autocomplete');
+      openAutoComplete = element.$.openDialog.querySelector('gr-autocomplete');
     });
 
     test('_isValidPath', () => {
@@ -77,9 +77,9 @@
         assert.isFalse(queryStub.called);
         // Setup _focused manually - in headless mode Chrome sometimes don't
         // setup focus. flush and/or flushAsynchronousOperations don't help
-        openAutoCcmplete._focused = true;
-        openAutoCcmplete.noDebounce = true;
-        openAutoCcmplete.text = 'src/test.cpp';
+        openAutoComplete._focused = true;
+        openAutoComplete.noDebounce = true;
+        openAutoComplete.text = 'src/test.cpp';
         assert.isTrue(queryStub.called);
         assert.isFalse(element.$.openDialog.disabled);
         MockInteractions.tap(element.$.openDialog.shadowRoot
@@ -95,8 +95,8 @@
       MockInteractions.tap(element.shadowRoot.querySelector('#open'));
       return showDialogSpy.lastCall.returnValue.then(() => {
         assert.isTrue(element.$.openDialog.disabled);
-        openAutoCcmplete.noDebounce = true;
-        openAutoCcmplete.text = 'src/test.cpp';
+        openAutoComplete.noDebounce = true;
+        openAutoComplete.text = 'src/test.cpp';
         assert.isFalse(element.$.openDialog.disabled);
         MockInteractions.tap(element.$.openDialog.shadowRoot
             .querySelector('gr-button'));
diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
index 1864598..1e08a5c 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.ts
@@ -200,7 +200,7 @@
   }
 
   _handlePathChanged(e: CustomEvent<string>) {
-    // TODO(TS) could be cleand up, it was added for type requirements
+    // TODO(TS) could be cleaned up, it was added for type requirements
     if (this._changeNum === undefined || !this._path) {
       return Promise.reject(new Error('changeNum or path undefined'));
     }
diff --git a/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper_test.js b/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper_test.js
index ea7bdc3..7ea3be3 100644
--- a/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper_test.js
+++ b/polygerrit-ui/app/elements/plugins/gr-attribute-helper/gr-attribute-helper_test.js
@@ -20,7 +20,7 @@
 import {GrAttributeHelper} from './gr-attribute-helper.js';
 
 Polymer({
-  is: 'gr-attrubute-helper-some-element',
+  is: 'gr-attribute-helper-some-element',
   properties: {
     fooBar: {
       type: Object,
@@ -29,7 +29,7 @@
   },
 });
 
-const basicFixture = fixtureFromElement('gr-attrubute-helper-some-element');
+const basicFixture = fixtureFromElement('gr-attribute-helper-some-element');
 
 suite('gr-attribute-helper tests', () => {
   let element;
diff --git a/polygerrit-ui/app/elements/plugins/gr-change-metadata-api/gr-change-metadata-api.ts b/polygerrit-ui/app/elements/plugins/gr-change-metadata-api/gr-change-metadata-api.ts
index 3a61bce..a03c5dc 100644
--- a/polygerrit-ui/app/elements/plugins/gr-change-metadata-api/gr-change-metadata-api.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-change-metadata-api/gr-change-metadata-api.ts
@@ -19,24 +19,24 @@
 import {HookApi} from '../../../api/hook';
 
 export class GrChangeMetadataApi implements ChangeMetadataPluginApi {
-  private _hook: HookApi | null;
+  private hook: HookApi | null;
 
   public plugin: PluginApi;
 
   constructor(plugin: PluginApi) {
     this.plugin = plugin;
-    this._hook = null;
+    this.hook = null;
   }
 
   _createHook() {
-    this._hook = this.plugin.hook('change-metadata-item');
+    this.hook = this.plugin.hook('change-metadata-item');
   }
 
   onLabelsChanged(callback: (value: unknown) => void) {
-    if (!this._hook) {
+    if (!this.hook) {
       this._createHook();
     }
-    this._hook!.onAttached((element: Element) =>
+    this.hook!.onAttached((element: Element) =>
       this.plugin.attributeHelper(element).bind('labels', callback)
     );
     return this;
diff --git a/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks.ts b/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks.ts
index d2568ad..3e8f0a4 100644
--- a/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks.ts
@@ -19,13 +19,13 @@
 import {HookApi, HookCallback} from '../../../api/hook';
 
 export class GrDomHooksManager {
-  private _hooks: Record<string, GrDomHook>;
+  private hooks: Record<string, GrDomHook>;
 
-  private _plugin: PluginApi;
+  private plugin: PluginApi;
 
   constructor(plugin: PluginApi) {
-    this._plugin = plugin;
-    this._hooks = {};
+    this.plugin = plugin;
+    this.hooks = {};
   }
 
   _getHookName(endpointName: string, moduleName?: string) {
@@ -36,37 +36,36 @@
       // TODO: this still can not prevent if plugin has invalid char
       // other than uppercase, but is the first step
       // https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name
-      const pluginName: string =
-        this._plugin.getPluginName() || 'unknown_plugin';
+      const pluginName: string = this.plugin.getPluginName() || 'unknownplugin';
       return pluginName.toLowerCase() + '-autogenerated-' + endpointName;
     }
   }
 
   getDomHook(endpointName: string, moduleName?: string) {
     const hookName = this._getHookName(endpointName, moduleName);
-    if (!this._hooks[hookName]) {
-      this._hooks[hookName] = new GrDomHook(hookName, moduleName);
+    if (!this.hooks[hookName]) {
+      this.hooks[hookName] = new GrDomHook(hookName, moduleName);
     }
-    return this._hooks[hookName];
+    return this.hooks[hookName];
   }
 }
 
 export class GrDomHook implements HookApi {
-  private _instances: HTMLElement[] = [];
+  private instances: HTMLElement[] = [];
 
-  private _attachCallbacks: HookCallback[] = [];
+  private attachCallbacks: HookCallback[] = [];
 
-  private _detachCallbacks: HookCallback[] = [];
+  private detachCallbacks: HookCallback[] = [];
 
-  private _moduleName: string;
+  private moduleName: string;
 
-  private _lastAttachedPromise: Promise<HTMLElement> | null = null;
+  private lastAttachedPromise: Promise<HTMLElement> | null = null;
 
   constructor(hookName: string, moduleName?: string) {
     if (moduleName) {
-      this._moduleName = moduleName;
+      this.moduleName = moduleName;
     } else {
-      this._moduleName = hookName;
+      this.moduleName = hookName;
       this._createPlaceholder(hookName);
     }
   }
@@ -89,16 +88,16 @@
   }
 
   handleInstanceDetached(instance: HTMLElement) {
-    const index = this._instances.indexOf(instance);
+    const index = this.instances.indexOf(instance);
     if (index !== -1) {
-      this._instances.splice(index, 1);
+      this.instances.splice(index, 1);
     }
-    this._detachCallbacks.forEach(callback => callback(instance));
+    this.detachCallbacks.forEach(callback => callback(instance));
   }
 
   handleInstanceAttached(instance: HTMLElement) {
-    this._instances.push(instance);
-    this._attachCallbacks.forEach(callback => callback(instance));
+    this.instances.push(instance);
+    this.attachCallbacks.forEach(callback => callback(instance));
   }
 
   /**
@@ -106,32 +105,32 @@
    * Returns a Promise, that's resolved when attachment is done.
    */
   getLastAttached(): Promise<HTMLElement> {
-    if (this._instances.length) {
-      return Promise.resolve(this._instances.slice(-1)[0]);
+    if (this.instances.length) {
+      return Promise.resolve(this.instances.slice(-1)[0]);
     }
-    if (!this._lastAttachedPromise) {
+    if (!this.lastAttachedPromise) {
       let resolve: HookCallback;
       const promise = new Promise<HTMLElement>(r => {
         resolve = r;
-        this._attachCallbacks.push(resolve);
+        this.attachCallbacks.push(resolve);
       });
-      this._lastAttachedPromise = promise.then((element: HTMLElement) => {
-        this._lastAttachedPromise = null;
-        const index = this._attachCallbacks.indexOf(resolve);
+      this.lastAttachedPromise = promise.then((element: HTMLElement) => {
+        this.lastAttachedPromise = null;
+        const index = this.attachCallbacks.indexOf(resolve);
         if (index !== -1) {
-          this._attachCallbacks.splice(index, 1);
+          this.attachCallbacks.splice(index, 1);
         }
         return element;
       });
     }
-    return this._lastAttachedPromise;
+    return this.lastAttachedPromise;
   }
 
   /**
    * Get all DOM hook elements.
    */
   getAllAttached() {
-    return this._instances;
+    return this.instances;
   }
 
   /**
@@ -139,7 +138,7 @@
    * is attached.
    */
   onAttached(callback: HookCallback) {
-    this._attachCallbacks.push(callback);
+    this.attachCallbacks.push(callback);
     return this;
   }
 
@@ -149,7 +148,7 @@
    *
    */
   onDetached(callback: HookCallback) {
-    this._detachCallbacks.push(callback);
+    this.detachCallbacks.push(callback);
     return this;
   }
 
@@ -157,6 +156,6 @@
    * Name of DOM hook element that will be installed into the endpoint.
    */
   getModuleName() {
-    return this._moduleName;
+    return this.moduleName;
   }
 }
diff --git a/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks_test.js b/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks_test.js
index 49223b9..883f2a6 100644
--- a/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks_test.js
+++ b/polygerrit-ui/app/elements/plugins/gr-dom-hooks/gr-dom-hooks_test.js
@@ -45,7 +45,7 @@
     });
 
     test('getModuleName()', () => {
-      const hookName = Object.keys(instance._hooks).pop();
+      const hookName = Object.keys(instance.hooks).pop();
       assert.equal(hookName, 'testplugin-autogenerated-foo-bar');
       assert.equal(hook.getModuleName(), 'testplugin-autogenerated-foo-bar');
     });
@@ -57,7 +57,7 @@
     });
 
     test('getModuleName()', () => {
-      const hookName = Object.keys(instance._hooks).pop();
+      const hookName = Object.keys(instance.hooks).pop();
       assert.equal(hookName, 'foo-bar my-el');
       assert.equal(hook.getModuleName(), 'my-el');
     });
diff --git a/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface.ts b/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface.ts
index 07d11ec..dcabc80 100644
--- a/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-popup-interface/gr-popup-interface.ts
@@ -27,23 +27,23 @@
 /**
  * Plugin popup API.
  * Provides method for opening and closing popups from plugin.
- * opt_moduleName is a name of custom element that will be automatically
+ * optmoduleName is a name of custom element that will be automatically
  * inserted on popup opening.
  */
 export class GrPopupInterface implements PopupPluginApi {
-  private _openingPromise: Promise<GrPopupInterface> | null = null;
+  private openingPromise: Promise<GrPopupInterface> | null = null;
 
-  private _popup: GrPluginPopup | null = null;
+  private popup: GrPluginPopup | null = null;
 
   constructor(
     readonly plugin: PluginApi,
-    private _moduleName: string | null = null
+    private moduleName: string | null = null
   ) {}
 
   _getElement() {
     // TODO(TS): maybe consider removing this if no one is using
     // anything other than native methods on the return
-    return (dom(this._popup) as unknown) as HTMLElement;
+    return (dom(this.popup) as unknown) as HTMLElement;
   }
 
   /**
@@ -52,34 +52,34 @@
    * if it was provided with constructor.
    */
   open(): Promise<PopupPluginApi> {
-    if (!this._openingPromise) {
-      this._openingPromise = this.plugin
+    if (!this.openingPromise) {
+      this.openingPromise = this.plugin
         .hook('plugin-overlay')
         .getLastAttached()
         .then(hookEl => {
           const popup = document.createElement('gr-plugin-popup');
-          if (this._moduleName) {
+          if (this.moduleName) {
             const el = popup.appendChild(
-              document.createElement(this._moduleName) as CustomPolymerPluginEl
+              document.createElement(this.moduleName) as CustomPolymerPluginEl
             );
             el.plugin = this.plugin;
           }
-          this._popup = hookEl.appendChild(popup);
+          this.popup = hookEl.appendChild(popup);
           flush();
-          return this._popup.open().then(() => this);
+          return this.popup.open().then(() => this);
         });
     }
-    return this._openingPromise;
+    return this.openingPromise;
   }
 
   /**
    * Hides the popup.
    */
   close() {
-    if (!this._popup) {
+    if (!this.popup) {
       return;
     }
-    this._popup.close();
-    this._openingPromise = null;
+    this.popup.close();
+    this.openingPromise = null;
   }
 }
diff --git a/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-repo-api.ts b/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-repo-api.ts
index e42ca08..0418edb 100644
--- a/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-repo-api.ts
+++ b/polygerrit-ui/app/elements/plugins/gr-repo-api/gr-repo-api.ts
@@ -29,7 +29,7 @@
 }
 
 export class GrRepoApi implements RepoPluginApi {
-  private _hook?: HookApi;
+  private hook?: HookApi;
 
   constructor(readonly plugin: PluginApi) {}
 
@@ -43,12 +43,12 @@
   }
 
   createCommand(title: string, callback: RepoCommandCallback) {
-    if (this._hook) {
+    if (this.hook) {
       console.warn('Already set up.');
       return this;
     }
-    this._hook = this._createHook(title);
-    this._hook.onAttached(element => {
+    this.hook = this._createHook(title);
+    this.hook.onAttached(element => {
       if (callback(element.repoName, element.config) === false) {
         element.hidden = true;
       }
@@ -57,11 +57,11 @@
   }
 
   onTap(callback: (event: Event) => boolean) {
-    if (!this._hook) {
+    if (!this.hook) {
       console.warn('Call createCommand first.');
       return this;
     }
-    this._hook.onAttached(element => {
+    this.hook.onAttached(element => {
       this.plugin.eventHelper(element).on('command-tap', callback);
     });
     return this;
diff --git a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
index 91ca402..59203d3 100644
--- a/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
+++ b/polygerrit-ui/app/elements/settings/gr-cla-view/gr-cla-view_html.ts
@@ -25,7 +25,7 @@
       margin-bottom: var(--spacing-m);
     }
     .agreementsUrl {
-      border: 1px solid #b0bdcc;
+      border: 1px solid var(--border-color);
       margin-bottom: var(--spacing-xl);
       margin-left: var(--spacing-xl);
       margin-right: var(--spacing-xl);
diff --git a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
index 3bb1458..4e6dd1a 100644
--- a/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-account-chip/gr-account-chip_html.ts
@@ -58,7 +58,6 @@
     gr-button.remove:focus {
       --gr-button: {
         @apply --gr-remove-button-style;
-        color: #333;
       }
     }
     gr-button.remove {
diff --git a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
index d105c5d..e55c8f1 100644
--- a/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-avatar/gr-avatar_html.ts
@@ -22,7 +22,7 @@
       display: inline-block;
       border-radius: 50%;
       background-size: cover;
-      background-color: var(--avatar-background-color, #f1f2f3);
+      background-color: var(--avatar-background-color, var(--gray-background));
     }
   </style>
 `;
diff --git a/polygerrit-ui/app/elements/shared/gr-button/gr-button.ts b/polygerrit-ui/app/elements/shared/gr-button/gr-button.ts
index 7a6ce2c..60b891e 100644
--- a/polygerrit-ui/app/elements/shared/gr-button/gr-button.ts
+++ b/polygerrit-ui/app/elements/shared/gr-button/gr-button.ts
@@ -61,7 +61,7 @@
   tooltip = '';
 
   // Note: don't assign a value to this, since constructor is called
-  // after created, the initial value maybe overriden by this
+  // after created, the initial value maybe overridden by this
   @property({type: String})
   _initialTabindex?: string;
 
diff --git a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
index 76bbd67..55408c0 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment-thread/gr-comment-thread_html.ts
@@ -23,12 +23,12 @@
       font-size: var(--font-size-normal);
       font-weight: var(--font-weight-normal);
       line-height: var(--line-height-normal);
-      /* Explicitly set the background color of the diff to be white. We
+      /* Explicitly set the background color of the diff. We
        * cannot use the diff content type ab because of the skip chunk preceding
        * it, diff processor assumes the chunk of type skip/ab can be collapsed
        * and hides our diff behind context control buttons.
        *  */
-      --dark-add-highlight-color: white;
+      --dark-add-highlight-color: var(--background-color-primary);
     }
     gr-button {
       margin-left: var(--spacing-m);
diff --git a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
index 2fbbd7c..119ed20 100644
--- a/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
+++ b/polygerrit-ui/app/elements/shared/gr-cursor-manager/gr-cursor-manager.ts
@@ -54,8 +54,8 @@
 export type Stop = HTMLElement | AbortStop;
 
 /**
- * Type guard and checker to check if a stop can be targetted.
- * Abort stops cannot be targetted.
+ * Type guard and checker to check if a stop can be targeted.
+ * Abort stops cannot be targeted.
  */
 export function isTargetable(stop: Stop): stop is HTMLElement {
   return !(stop instanceof AbortStop);
diff --git a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
index d2f003b..4c2a417 100644
--- a/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
+++ b/polygerrit-ui/app/elements/shared/gr-download-commands/gr-download-commands.ts
@@ -52,7 +52,7 @@
 
   // TODO(TS): maybe default to [] as only used in dom-repeat
   @property({type: Array})
-  comamnds?: Command[];
+  commands?: Command[];
 
   @property({type: Boolean})
   _loggedIn = false;
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
index 3fce16e..888f34f 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list.ts
@@ -32,7 +32,7 @@
 import {NormalizedFileInfo} from '../../change/gr-file-list/gr-file-list';
 
 /**
- * Requred values are text and value. mobileText and triggerText will
+ * Required values are text and value. mobileText and triggerText will
  * fall back to text if not provided.
  *
  * If bottomText is not provided, nothing will display on the second
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
index e67e1f6..b8f0161 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
@@ -110,13 +110,13 @@
       @property({type: String})
       containerId = 'gr-hovercard-container';
 
-      private _hideDebouncer: Debouncer | null = null;
+      private hideDebouncer: Debouncer | null = null;
 
-      private _showDebouncer: Debouncer | null = null;
+      private showDebouncer: Debouncer | null = null;
 
-      private _isScheduledToShow?: boolean;
+      private isScheduledToShow?: boolean;
 
-      private _isScheduledToHide?: boolean;
+      private isScheduledToHide?: boolean;
 
       /** @override */
       attached() {
@@ -174,24 +174,24 @@
 
       debounceHide() {
         this.cancelShowDebouncer();
-        if (!this._isShowing || this._isScheduledToHide) return;
-        this._isScheduledToHide = true;
-        this._hideDebouncer = Debouncer.debounce(
-          this._hideDebouncer,
+        if (!this._isShowing || this.isScheduledToHide) return;
+        this.isScheduledToHide = true;
+        this.hideDebouncer = Debouncer.debounce(
+          this.hideDebouncer,
           timeOut.after(HIDE_DELAY_MS),
           () => {
             // This happens when hide immediately through click or mouse leave
             // on the hovercard
-            if (!this._isScheduledToHide) return;
+            if (!this.isScheduledToHide) return;
             this.hide();
           }
         );
       }
 
       cancelHideDebouncer() {
-        if (this._hideDebouncer) {
-          this._hideDebouncer.cancel();
-          this._isScheduledToHide = false;
+        if (this.hideDebouncer) {
+          this.hideDebouncer.cancel();
+          this.isScheduledToHide = false;
         }
       }
 
@@ -305,23 +305,23 @@
        */
       debounceShowBy(delayMs: number) {
         this.cancelHideDebouncer();
-        if (this._isShowing || this._isScheduledToShow) return;
-        this._isScheduledToShow = true;
-        this._showDebouncer = Debouncer.debounce(
-          this._showDebouncer,
+        if (this._isShowing || this.isScheduledToShow) return;
+        this.isScheduledToShow = true;
+        this.showDebouncer = Debouncer.debounce(
+          this.showDebouncer,
           timeOut.after(delayMs),
           () => {
             // This happens when the mouse leaves the target before the delay is over.
-            if (!this._isScheduledToShow) return;
+            if (!this.isScheduledToShow) return;
             this.show();
           }
         );
       }
 
       cancelShowDebouncer() {
-        if (this._showDebouncer) {
-          this._showDebouncer.cancel();
-          this._isScheduledToShow = false;
+        if (this.showDebouncer) {
+          this.showDebouncer.cancel();
+          this.isScheduledToShow = false;
         }
       }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js
index 6b2e620..628b1e9 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js
@@ -120,18 +120,18 @@
     button.dispatchEvent(new CustomEvent('mouseenter'));
 
     await enterPromise;
-    assert.isTrue(element._isScheduledToShow);
-    element._showDebouncer.flush();
+    assert.isTrue(element.isScheduledToShow);
+    element.showDebouncer.flush();
     assert.isTrue(element._isShowing);
-    assert.isFalse(element._isScheduledToShow);
+    assert.isFalse(element.isScheduledToShow);
 
     button.dispatchEvent(new CustomEvent('mouseleave'));
 
     await leavePromise;
-    assert.isTrue(element._isScheduledToHide);
+    assert.isTrue(element.isScheduledToHide);
     assert.isTrue(element._isShowing);
-    element._hideDebouncer.flush();
-    assert.isFalse(element._isScheduledToShow);
+    element.hideDebouncer.flush();
+    assert.isFalse(element.isScheduledToShow);
     assert.isFalse(element._isShowing);
 
     button.removeEventListener('mouseenter', enterResolve);
@@ -152,11 +152,11 @@
     button.dispatchEvent(new CustomEvent('mouseenter'));
 
     await enterPromise;
-    assert.isTrue(element._isScheduledToShow);
+    assert.isTrue(element.isScheduledToShow);
     MockInteractions.tap(button);
 
     await clickPromise;
-    assert.isFalse(element._isScheduledToShow);
+    assert.isFalse(element.isScheduledToShow);
     assert.isFalse(element._isShowing);
 
     button.removeEventListener('mouseenter', enterResolve);
diff --git a/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts b/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
index 0a3ef5b..7745da8 100644
--- a/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
+++ b/polygerrit-ui/app/elements/shared/gr-icons/gr-icons.ts
@@ -128,6 +128,8 @@
       <g id="message"><path d="M0 0h24v24H0z" fill="none"/><path d="M20 2H4c-1.1 0-1.99.9-1.99 2L2 22l4-4h14c1.1 0 2-.9 2-2V4c0-1.1-.9-2-2-2zm-2 12H6v-2h12v2zm0-3H6V9h12v2zm0-3H6V6h12v2z"/></g>
       <!-- This SVG is a copy from material.io https://material.io/icons/#launch-->
       <g id="launch"><path d="M0 0h24v24H0z" fill="none"/><path d="M19 19H5V5h7V3H5c-1.11 0-2 .9-2 2v14c0 1.1.89 2 2 2h14c1.1 0 2-.9 2-2v-7h-2v7zM14 3v2h3.59l-9.83 9.83 1.41 1.41L19 6.41V10h2V3h-7z"/></g>
+      <!-- This SVG is a copy from material.io https://material.io/icons/#filter-->
+      <g id="filter"><path d="M0,0h24 M24,24H0" fill="none"/><path d="M4.25,5.61C6.27,8.2,10,13,10,13v6c0,0.55,0.45,1,1,1h2c0.55,0,1-0.45,1-1v-6c0,0,3.72-4.8,5.74-7.39 C20.25,4.95,19.78,4,18.95,4H5.04C4.21,4,3.74,4.95,4.25,5.61z"/><path d="M0,0h24v24H0V0z" fill="none"/></g>
       <!-- This is just a placeholder, i.e. an empty icon that has the same size as a normal icon. -->
       <g id="placeholder"><path d="M0 0h24v24H0z" fill="none"/></g>
     </defs>
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
index 2f2b5ce..a4c6974 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-change-actions-js-api.ts
@@ -60,7 +60,7 @@
 }
 
 export class GrChangeActionsInterface implements ChangeActionsPluginApi {
-  private _el?: GrChangeActionsElement;
+  private el?: GrChangeActionsElement;
 
   RevisionActions = RevisionActions;
 
@@ -80,7 +80,7 @@
       console.warn('changeActions() is not ready');
       return;
     }
-    this._el = el;
+    this.el = el;
   }
 
   /**
@@ -88,7 +88,7 @@
    * element and retrieve if the interface was created before element.
    */
   private ensureEl(): GrChangeActionsElement {
-    if (!this._el) {
+    if (!this.el) {
       const sharedApiElement = appContext.jsApiService;
       this.setEl(
         (sharedApiElement.getElement(
@@ -96,7 +96,7 @@
         ) as unknown) as GrChangeActionsElement
       );
     }
-    return this._el!;
+    return this.el!;
   }
 
   addPrimaryActionKey(key: PrimaryActionKey) {
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
index 27bc591..7f9218a 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-gerrit.ts
@@ -250,7 +250,7 @@
    *   });
    * });
    *
-   * // Listen on your-special-event from pluignB
+   * // Listen on your-special-event from pluginB
    * Gerrit.install(pluginB => {
    *   Gerrit.on("your-special-event", ({plugin}) => {
    *     // do something, plugin is pluginA
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
index 6a8a0dd..12a4056 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface_test.js
@@ -426,7 +426,7 @@
             // eslint-disable-next-line no-invalid-this
             const grPopupInterface = this;
             assert.equal(grPopupInterface.plugin, plugin);
-            assert.equal(grPopupInterface._moduleName, 'some-name');
+            assert.equal(grPopupInterface.moduleName, 'some-name');
           });
       plugin.popup('some-name');
       assert.isTrue(openStub.calledOnce);
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context.ts
index 21e4876..2135c30 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-action-context.ts
@@ -28,7 +28,7 @@
 }
 
 export class GrPluginActionContext {
-  private _popups: PopupPluginApi[] = [];
+  private popups: PopupPluginApi[] = [];
 
   constructor(
     public readonly plugin: PluginApi,
@@ -44,15 +44,15 @@
         throw new Error('Popup element not found');
       }
       popupEl.appendChild(element);
-      this._popups.push(popApi);
+      this.popups.push(popApi);
     });
   }
 
   hide() {
-    for (const popupApi of this._popups) {
+    for (const popupApi of this.popups) {
       popupApi.close();
     }
-    this._popups.splice(0);
+    this.popups.splice(0);
   }
 
   refresh() {
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
index 2752c74..82df2fa 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-endpoints.ts
@@ -51,10 +51,10 @@
 
   private readonly _importedUrls = new Set<string>();
 
-  private _pluginLoaded = false;
+  private pluginLoaded = false;
 
   setPluginsReady() {
-    this._pluginLoaded = true;
+    this.pluginLoaded = true;
   }
 
   onNewEndpoint(endpoint: string, callback: Callback) {
@@ -125,7 +125,7 @@
     // one register before plugins ready
     // the other done after, then only the later one will have the callbacks
     // invoked.
-    if (this._pluginLoaded && this._callbacks.has(endpoint)) {
+    if (this.pluginLoaded && this._callbacks.has(endpoint)) {
       this._callbacks.get(endpoint)!.forEach(callback => callback(moduleInfo));
     }
   }
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
index 8c0fce26..db34e5a 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader.ts
@@ -74,7 +74,7 @@
 const UNKNOWN_PLUGIN_PREFIX = '__$$__';
 
 // Current API version for Plugin,
-// plugins with incompatible version will not be laoded.
+// plugins with incompatible version will not be loaded.
 const API_VERSION = '0.1';
 
 /**
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader_test.js b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader_test.js
index 6b62291..f5b1fca 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-plugin-loader_test.js
@@ -225,7 +225,7 @@
     assert.isTrue(alertStub.calledTwice);
   });
 
-  test('plugins installed failed becasue of wrong version', async () => {
+  test('plugins installed failed because of wrong version', async () => {
     const plugins = [
       'http://test.com/plugins/foo/static/test.js',
       'http://test.com/plugins/bar/static/test.js',
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
index 45ffdcd9..e7843af 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-public-js-api.ts
@@ -78,14 +78,14 @@
 export class Plugin implements PluginApi {
   readonly _url?: URL;
 
-  private _domHooks: GrDomHooksManager;
+  private domHooks: GrDomHooksManager;
 
   private readonly _name: string = PLUGIN_NAME_NOT_SET;
 
   private readonly jsApi = appContext.jsApiService;
 
   constructor(url?: string) {
-    this._domHooks = new GrDomHooksManager(this);
+    this.domHooks = new GrDomHooksManager(this);
 
     if (!url) {
       console.warn(
@@ -151,7 +151,7 @@
     const type =
       options && options.replace ? EndpointType.REPLACE : EndpointType.DECORATE;
     const slot = (options && options.slot) || '';
-    const domHook = this._domHooks.getDomHook(endpoint, moduleName);
+    const domHook = this.domHooks.getDomHook(endpoint, moduleName);
     moduleName = moduleName || domHook.getModuleName();
     getPluginEndpoints().registerModule(this, {
       slot,
diff --git a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip_html.ts b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip_html.ts
index a335db7..8581a0c 100644
--- a/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-linked-chip/gr-linked-chip_html.ts
@@ -46,7 +46,6 @@
     gr-button.remove:focus {
       --gr-button: {
         @apply --gr-remove-button-style;
-        color: #333;
       }
     }
     gr-button.remove {
diff --git a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
index d29cba7..20e5296 100644
--- a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
+++ b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay.ts
@@ -56,7 +56,7 @@
    * @event fullscreen-overlay-opened
    */
 
-  private _fullScreenOpen = false;
+  private fullScreenOpen = false;
 
   private _boundHandleClose: () => void = () => super.close();
 
@@ -99,7 +99,7 @@
       super.open.apply(this);
       if (this._isMobile()) {
         fireEvent(this, 'fullscreen-overlay-opened');
-        this._fullScreenOpen = true;
+        this.fullScreenOpen = true;
       }
       this._awaitOpen(resolve, reject);
     });
@@ -112,9 +112,9 @@
   // called after iron-overlay is closed. Does not actually close the overlay
   _overlayClosed() {
     window.removeEventListener('popstate', this._boundHandleClose);
-    if (this._fullScreenOpen) {
+    if (this.fullScreenOpen) {
       fireEvent(this, 'fullscreen-overlay-closed');
-      this._fullScreenOpen = false;
+      this.fullScreenOpen = false;
     }
     if (this.returnFocusTo) {
       this.returnFocusTo.focus();
diff --git a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay_test.js b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay_test.js
index 4b6ae34..72c3399 100644
--- a/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-overlay/gr-overlay_test.js
@@ -57,11 +57,11 @@
     await element.open();
 
     assert.isTrue(element._isMobile.called);
-    assert.isTrue(element._fullScreenOpen);
+    assert.isTrue(element.fullScreenOpen);
     assert.isTrue(openHandler.called);
 
     element._overlayClosed();
-    assert.isFalse(element._fullScreenOpen);
+    assert.isFalse(element.fullScreenOpen);
     assert.isTrue(closeHandler.called);
   });
 
@@ -75,11 +75,11 @@
     await element.open();
 
     assert.isTrue(element._isMobile.called);
-    assert.isFalse(element._fullScreenOpen);
+    assert.isFalse(element.fullScreenOpen);
     assert.isFalse(openHandler.called);
 
     element._overlayClosed();
-    assert.isFalse(element._fullScreenOpen);
+    assert.isFalse(element.fullScreenOpen);
     assert.isFalse(closeHandler.called);
   });
 });
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
index fa2a28e..89abd57 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-apis/gr-rest-api-helper.ts
@@ -75,7 +75,7 @@
 export class SiteBasedCache {
   // TODO(TS): Type looks unusual. Fix it.
   // Container of per-canonical-path caches.
-  private readonly _data = new Map<
+  private readonly data = new Map<
     string | undefined,
     unknown | Map<string, ParsedJSON | null>
   >();
@@ -93,13 +93,13 @@
 
   // Returns the cache for the current canonical path.
   _cache(): Map<string, unknown> {
-    if (!this._data.has(window.CANONICAL_PATH)) {
-      this._data.set(
+    if (!this.data.has(window.CANONICAL_PATH)) {
+      this.data.set(
         window.CANONICAL_PATH,
         new Map<string, ParsedJSON | null>()
       );
     }
-    return this._data.get(window.CANONICAL_PATH) as Map<
+    return this.data.get(window.CANONICAL_PATH) as Map<
       string,
       ParsedJSON | null
     >;
@@ -140,7 +140,7 @@
         newMap.set(key, value);
       }
     }
-    this._data.set(window.CANONICAL_PATH, newMap);
+    this.data.set(window.CANONICAL_PATH, newMap);
   }
 }
 
@@ -149,25 +149,25 @@
 };
 
 export class FetchPromisesCache {
-  private _data: FetchPromisesCacheData;
+  private data: FetchPromisesCacheData;
 
   constructor() {
-    this._data = {};
+    this.data = {};
   }
 
   public testOnlyGetData() {
-    return this._data;
+    return this.data;
   }
 
   /**
    * @return true only if a value for a key sets and it is not undefined
    */
   has(key: string): boolean {
-    return !!this._data[key];
+    return !!this.data[key];
   }
 
   get(key: string) {
-    return this._data[key];
+    return this.data[key];
   }
 
   /**
@@ -175,17 +175,17 @@
    *     mark key as deleted.
    */
   set(key: string, value: Promise<ParsedJSON | undefined> | undefined) {
-    this._data[key] = value;
+    this.data[key] = value;
   }
 
   invalidatePrefix(prefix: string) {
     const newData: FetchPromisesCacheData = {};
-    Object.entries(this._data).forEach(([key, value]) => {
+    Object.entries(this.data).forEach(([key, value]) => {
       if (!key.startsWith(prefix)) {
         newData[key] = value;
       }
     });
-    this._data = newData;
+    this.data = newData;
   }
 }
 export type FetchParams = {
@@ -457,7 +457,7 @@
    * Send an XHR.
    *
    * @return Promise resolves to Response/ParsedJSON only if the request is successful
-   *     (i.e. no exception and response.ok is trsue). If response fails then
+   *     (i.e. no exception and response.ok is true). If response fails then
    *     promise resolves either to void if errFn is set or rejects if errFn
    *     is not set   */
   send(req: SendRequest): Promise<Response | ParsedJSON | undefined> {
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.ts
index 1a1062c..95e06c0 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-reviewer-updates-parser.ts
@@ -81,9 +81,9 @@
   // type. This class should be refactored to avoid reassignment.
   private readonly result: ChangeInfoParserInput;
 
-  private _batch: ParserBatch | null = null;
+  private batch: ParserBatch | null = null;
 
-  private _updateItems: {[accountId: string]: UpdateItem} | null = null;
+  private updateItems: {[accountId: string]: UpdateItem} | null = null;
 
   private readonly _lastState: {[accountId: string]: ReviewerState} = {};
 
@@ -105,7 +105,7 @@
    * Is a part of _groupUpdates(). Creates a new batch of updates.
    */
   private _startBatch(update: ReviewerUpdateInfo): ParserBatch {
-    this._updateItems = {};
+    this.updateItems = {};
     return {
       author: update.updated_by,
       date: update.updated,
@@ -121,7 +121,7 @@
    */
   private _completeBatch(batch: ParserBatch) {
     const items = [];
-    for (const [accountId, item] of Object.entries(this._updateItems ?? {})) {
+    for (const [accountId, item] of Object.entries(this.updateItems ?? {})) {
       if (this._lastState[accountId] !== item.state) {
         this._lastState[accountId] = item.state;
         items.push(item);
@@ -142,27 +142,27 @@
   _groupUpdates(): ParserBatchWithNonEmptyUpdates[] {
     const updates = this.result.reviewer_updates;
     const newUpdates = updates.reduce((newUpdates, update) => {
-      if (!this._batch) {
-        this._batch = this._startBatch(update);
+      if (!this.batch) {
+        this.batch = this._startBatch(update);
       }
       const updateDate = parseDate(update.updated).getTime();
-      const batchUpdateDate = parseDate(this._batch.date).getTime();
+      const batchUpdateDate = parseDate(this.batch.date).getTime();
       const reviewerId = accountKey(update.reviewer);
       if (
         updateDate - batchUpdateDate > REVIEWER_UPDATE_THRESHOLD_MILLIS ||
-        update.updated_by._account_id !== this._batch.author._account_id
+        update.updated_by._account_id !== this.batch.author._account_id
       ) {
         // Next sequential update should form new group.
-        this._completeBatch(this._batch);
-        if (isParserBatchWithNonEmptyUpdates(this._batch)) {
-          newUpdates.push(this._batch);
+        this._completeBatch(this.batch);
+        if (isParserBatchWithNonEmptyUpdates(this.batch)) {
+          newUpdates.push(this.batch);
         }
-        this._batch = this._startBatch(update);
+        this.batch = this._startBatch(update);
       }
-      // _startBatch assigns _updateItems. When _groupUpdates is calling,
-      // _batch and _updateItems are not set => _startBatch is called. The
-      // _startBatch method assigns _updateItems
-      const updateItems = this._updateItems!;
+      // _startBatch assigns updateItems. When _groupUpdates is calling,
+      // batch and updateItems are not set => _startBatch is called. The
+      // _startBatch method assigns updateItems
+      const updateItems = this.updateItems!;
       updateItems[reviewerId] = {
         reviewer: update.reviewer,
         state: update.state,
@@ -174,8 +174,8 @@
     }, [] as ParserBatchWithNonEmptyUpdates[]);
     // reviewer_updates always has at least 1 item
     // (otherwise parse is not created) => updates.reduce calls callback
-    // at least once and callback assigns this._batch
-    const batch = this._batch!;
+    // at least once and callback assigns this.batch
+    const batch = this.batch!;
     this._completeBatch(batch);
     if (isParserBatchWithNonEmptyUpdates(batch)) {
       newUpdates.push(batch);
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
index b0b40dd..885db2a 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
@@ -112,7 +112,7 @@
   @property({type: Boolean})
   hideBorder = false;
 
-  /** Text input should be rendered in monspace font.  */
+  /** Text input should be rendered in monospace font.  */
   @property({type: Boolean})
   monospace = false;
 
diff --git a/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts b/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
index 77d2d00..75ad608 100644
--- a/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
+++ b/polygerrit-ui/app/mixins/gr-tooltip-mixin/gr-tooltip-mixin.ts
@@ -69,13 +69,13 @@
       // Handler for mouseenter event
       private mouseenterHandler?: (e: MouseEvent) => void;
 
-      // Hanlder for scrolling on window
+      // Handler for scrolling on window
       private readonly windowScrollHandler: () => void;
 
-      // Hanlder for showing the tooltip, will be attached to certain events
+      // Handler for showing the tooltip, will be attached to certain events
       private readonly showHandler: () => void;
 
-      // Hanlder for hiding the tooltip, will be attached to certain events
+      // Handler for hiding the tooltip, will be attached to certain events
       private readonly hideHandler: () => void;
 
       // eslint-disable-next-line @typescript-eslint/no-unused-vars, @typescript-eslint/no-explicit-any
diff --git a/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts b/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
index 662d6bf..57e034f 100644
--- a/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
+++ b/polygerrit-ui/app/mixins/iron-fit-mixin/iron-fit-mixin.ts
@@ -29,7 +29,7 @@
 // is used. To ensure that this import can't be avoided, the second parameter
 // is added. Usage example:
 // class Element extends IronFitMixin(PolymerElement, IronFitBehavior as IronFitBehavior)
-// The code 'IronFitBehavior as IronFitBehavior' required, becuase IronFitBehavior
+// The code 'IronFitBehavior as IronFitBehavior' required, because IronFitBehavior
 // defined as an object, not as IronFitBehavior instance.
 
 export const IronFitMixin = <T extends Constructor<PolymerElement>>(
diff --git a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
index 63a05aa..ab85b87 100644
--- a/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
+++ b/polygerrit-ui/app/mixins/keyboard-shortcut-mixin/keyboard-shortcut-mixin.ts
@@ -544,7 +544,7 @@
 }
 
 /**
- * Shortcut manager, holds all hosts, bindings and listners.
+ * Shortcut manager, holds all hosts, bindings and listeners.
  */
 export class ShortcutManager {
   private readonly activeHosts = new Map<PolymerElement, Map<string, string>>();
diff --git a/polygerrit-ui/app/node_modules_licenses/licenses.ts b/polygerrit-ui/app/node_modules_licenses/licenses.ts
index 7a6253b..f03c7e6 100644
--- a/polygerrit-ui/app/node_modules_licenses/licenses.ts
+++ b/polygerrit-ui/app/node_modules_licenses/licenses.ts
@@ -254,6 +254,14 @@
     license: SharedLicenses.Polymer2017
   },
   {
+    name: "@types/resize-observer-browser",
+    license: {
+      name: 'DefinitelyTyped',
+      type: LicenseTypes.Mit,
+      packageLicenseFile: "LICENSE"
+    }
+  },
+  {
     name: "@webcomponents/shadycss",
     license: SharedLicenses.Polymer2017
   },
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index 3351386..5e15990 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -25,6 +25,7 @@
     "@polymer/paper-tabs": "^3.1.0",
     "@polymer/paper-toggle-button": "^3.0.1",
     "@polymer/polymer": "^3.4.1",
+    "@types/resize-observer-browser": "^0.1.5",
     "@webcomponents/shadycss": "^1.9.2",
     "@webcomponents/webcomponentsjs": "^1.3.3",
     "ba-linkify": "file:../../lib/ba-linkify/src/",
diff --git a/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider.ts b/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider.ts
index 7969b84..5818003 100644
--- a/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider.ts
+++ b/polygerrit-ui/app/scripts/gr-email-suggestions-provider/gr-email-suggestions-provider.ts
@@ -19,10 +19,10 @@
 import {AccountInfo} from '../../types/common';
 
 export class GrEmailSuggestionsProvider {
-  constructor(private _restAPI: RestApiService) {}
+  constructor(private restAPI: RestApiService) {}
 
   getSuggestions(input: string) {
-    return this._restAPI.getSuggestedAccounts(`${input}`).then(accounts => {
+    return this.restAPI.getSuggestedAccounts(`${input}`).then(accounts => {
       if (!accounts) {
         return [];
       }
diff --git a/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider.ts b/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider.ts
index 1cf1c39..ff113fb 100644
--- a/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider.ts
+++ b/polygerrit-ui/app/scripts/gr-group-suggestions-provider/gr-group-suggestions-provider.ts
@@ -19,10 +19,10 @@
 import {GroupBaseInfo} from '../../types/common';
 
 export class GrGroupSuggestionsProvider {
-  constructor(private _restAPI: RestApiService) {}
+  constructor(private restAPI: RestApiService) {}
 
   getSuggestions(input: string) {
-    return this._restAPI.getSuggestedGroups(`${input}`).then(groups => {
+    return this.restAPI.getSuggestedGroups(`${input}`).then(groups => {
       if (!groups) {
         return [];
       }
diff --git a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider.ts b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider.ts
index 1572ba1..45116aa 100644
--- a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider.ts
+++ b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider.ts
@@ -73,13 +73,13 @@
     }
   }
 
-  private _initPromise?: Promise<void>;
+  private initPromise?: Promise<void>;
 
-  private _config?: ServerInfo;
+  private config?: ServerInfo;
 
-  private _loggedIn = false;
+  private loggedIn = false;
 
-  private _initialized = false;
+  private initialized = false;
 
   private constructor(
     private readonly _restAPI: RestApiService,
@@ -87,26 +87,25 @@
   ) {}
 
   init() {
-    if (this._initPromise) {
-      return this._initPromise;
+    if (this.initPromise) {
+      return this.initPromise;
     }
     const getConfigPromise = this._restAPI.getConfig().then(cfg => {
-      this._config = cfg;
+      this.config = cfg;
     });
     const getLoggedInPromise = this._restAPI.getLoggedIn().then(loggedIn => {
-      this._loggedIn = loggedIn;
+      this.loggedIn = loggedIn;
     });
-    this._initPromise = Promise.all([
-      getConfigPromise,
-      getLoggedInPromise,
-    ]).then(() => {
-      this._initialized = true;
-    });
-    return this._initPromise;
+    this.initPromise = Promise.all([getConfigPromise, getLoggedInPromise]).then(
+      () => {
+        this.initialized = true;
+      }
+    );
+    return this.initPromise;
   }
 
   getSuggestions(input: string): Promise<Suggestion[]> {
-    if (!this._initialized || !this._loggedIn) {
+    if (!this.initialized || !this.loggedIn) {
       return Promise.resolve([]);
     }
 
@@ -117,7 +116,7 @@
     if (isReviewerAccountSuggestion(suggestion)) {
       // Reviewer is an account suggestion from getChangeSuggestedReviewers.
       return {
-        name: getAccountDisplayName(this._config, suggestion.account),
+        name: getAccountDisplayName(this.config, suggestion.account),
         value: suggestion,
       };
     }
@@ -133,7 +132,7 @@
     if (isAccountSuggestions(suggestion)) {
       // Reviewer is an account suggestion from getSuggestedAccounts.
       return {
-        name: getAccountDisplayName(this._config, suggestion),
+        name: getAccountDisplayName(this.config, suggestion),
         value: {account: suggestion, count: 1},
       };
     }
diff --git a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
index c7de24a..d3cad45 100644
--- a/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
+++ b/polygerrit-ui/app/scripts/gr-reviewer-suggestions-provider/gr-reviewer-suggestions-provider_test.js
@@ -130,7 +130,7 @@
           value: {account: {}},
         });
 
-        provider._config = {
+        provider.config = {
           user: {
             anonymous_coward_name: 'Anonymous Coward Name',
           },
@@ -179,10 +179,10 @@
       });
 
       test('getSuggestions short circuits when logged out', () => {
-        provider._loggedIn = false;
+        provider.loggedIn = false;
         return provider.getSuggestions('').then(() => {
           assert.isFalse(getChangeSuggestedReviewersStub.called);
-          provider._loggedIn = true;
+          provider.loggedIn = true;
           return provider.getSuggestions('').then(() => {
             assert.isTrue(getChangeSuggestedReviewersStub.called);
           });
diff --git a/polygerrit-ui/app/services/checks/checks-util.ts b/polygerrit-ui/app/services/checks/checks-util.ts
index 176464f..1613359 100644
--- a/polygerrit-ui/app/services/checks/checks-util.ts
+++ b/polygerrit-ui/app/services/checks/checks-util.ts
@@ -24,7 +24,7 @@
   return undefined;
 }
 
-export function iconForCategory(category: Category) {
+export function iconForCategory(category: Category | 'SUCCESS') {
   switch (category) {
     case Category.ERROR:
       return 'error';
@@ -32,6 +32,8 @@
       return 'info-outline';
     case Category.WARNING:
       return 'warning';
+    case 'SUCCESS':
+      return 'check-circle-outline';
     default:
       assertNever(category, `Unsupported category: ${category}`);
   }
diff --git a/polygerrit-ui/app/services/gr-auth/gr-auth_impl.ts b/polygerrit-ui/app/services/gr-auth/gr-auth_impl.ts
index 8fe7c35..6fadfde 100644
--- a/polygerrit-ui/app/services/gr-auth/gr-auth_impl.ts
+++ b/polygerrit-ui/app/services/gr-auth/gr-auth_impl.ts
@@ -61,26 +61,26 @@
 
   static CREDS_EXPIRED_MSG = 'Credentials expired.';
 
-  private _authCheckPromise?: Promise<Response>;
+  private authCheckPromise?: Promise<Response>;
 
   private _last_auth_check_time: number = Date.now();
 
   private _status = AuthStatus.UNDETERMINED;
 
-  private _retriesLeft = MAX_GET_TOKEN_RETRIES;
+  private retriesLeft = MAX_GET_TOKEN_RETRIES;
 
-  private _cachedTokenPromise: Promise<Token | null> | null = null;
+  private cachedTokenPromise: Promise<Token | null> | null = null;
 
-  private _type?: AuthType;
+  private type?: AuthType;
 
-  private _defaultOptions: AuthRequestInit = {};
+  private defaultOptions: AuthRequestInit = {};
 
-  private _getToken: GetTokenCallback;
+  private getToken: GetTokenCallback;
 
   public eventEmitter: EventEmitterService;
 
   constructor(eventEmitter: EventEmitterService) {
-    this._getToken = () => Promise.resolve(this._cachedTokenPromise);
+    this.getToken = () => Promise.resolve(this.cachedTokenPromise);
     this.eventEmitter = eventEmitter;
   }
 
@@ -93,15 +93,15 @@
    */
   authCheck(): Promise<boolean> {
     if (
-      !this._authCheckPromise ||
+      !this.authCheckPromise ||
       Date.now() - this._last_auth_check_time > MAX_AUTH_CHECK_WAIT_TIME_MS
     ) {
       // Refetch after last check expired
-      this._authCheckPromise = fetch(`${this.baseUrl}/auth-check`);
+      this.authCheckPromise = fetch(`${this.baseUrl}/auth-check`);
       this._last_auth_check_time = Date.now();
     }
 
-    return this._authCheckPromise
+    return this.authCheckPromise
       .then(res => {
         // auth-check will return 204 if authed
         // treat the rest as unauthed
@@ -115,14 +115,14 @@
       })
       .catch(() => {
         this._setStatus(AuthStatus.ERROR);
-        // Reset _authCheckPromise to avoid caching the failed promise
-        this._authCheckPromise = undefined;
+        // Reset authCheckPromise to avoid caching the failed promise
+        this.authCheckPromise = undefined;
         return false;
       });
   }
 
   clearCache() {
-    this._authCheckPromise = undefined;
+    this.authCheckPromise = undefined;
   }
 
   private _setStatus(status: AuthStatus) {
@@ -149,15 +149,15 @@
    * Enable cross-domain authentication using OAuth access token.
    */
   setup(getToken: GetTokenCallback, defaultOptions: DefaultAuthOptions) {
-    this._retriesLeft = MAX_GET_TOKEN_RETRIES;
+    this.retriesLeft = MAX_GET_TOKEN_RETRIES;
     if (getToken) {
-      this._type = AuthType.ACCESS_TOKEN;
-      this._cachedTokenPromise = null;
-      this._getToken = getToken;
+      this.type = AuthType.ACCESS_TOKEN;
+      this.cachedTokenPromise = null;
+      this.getToken = getToken;
     }
-    this._defaultOptions = {};
+    this.defaultOptions = {};
     if (defaultOptions) {
-      this._defaultOptions.credentials = defaultOptions.credentials;
+      this.defaultOptions.credentials = defaultOptions.credentials;
     }
   }
 
@@ -167,10 +167,10 @@
   fetch(url: string, opt_options?: AuthRequestInit): Promise<Response> {
     const options: AuthRequestInitWithHeaders = {
       headers: new Headers(),
-      ...this._defaultOptions,
+      ...this.defaultOptions,
       ...opt_options,
     };
-    if (this._type === AuthType.ACCESS_TOKEN) {
+    if (this.type === AuthType.ACCESS_TOKEN) {
       return this._getAccessToken().then(accessToken =>
         this._fetchWithAccessToken(url, options, accessToken)
       );
@@ -224,17 +224,17 @@
   }
 
   private _getAccessToken(): Promise<string | null> {
-    if (!this._cachedTokenPromise) {
-      this._cachedTokenPromise = this._getToken();
+    if (!this.cachedTokenPromise) {
+      this.cachedTokenPromise = this.getToken();
     }
-    return this._cachedTokenPromise.then(token => {
+    return this.cachedTokenPromise.then(token => {
       if (this._isTokenValid(token)) {
-        this._retriesLeft = MAX_GET_TOKEN_RETRIES;
+        this.retriesLeft = MAX_GET_TOKEN_RETRIES;
         return token.access_token;
       }
-      if (this._retriesLeft > 0) {
-        this._retriesLeft--;
-        this._cachedTokenPromise = null;
+      if (this.retriesLeft > 0) {
+        this.retriesLeft--;
+        this.cachedTokenPromise = null;
         return this._getAccessToken();
       }
       // Fall back to anonymous access.
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
index 4ca983a..4196513 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting.ts
@@ -61,7 +61,7 @@
   timeEnd(name: string, eventDetails?: EventDetails): void;
   /**
    * Reports just line timeEnd, but additionally reports an average given a
-   * denominator and a separate reporiting name for the average.
+   * denominator and a separate reporting name for the average.
    *
    * @param name Timing name.
    * @param averageName Average timing name.
@@ -74,7 +74,7 @@
     denominator: number
   ): void;
   /**
-   * Get a timer object to for reporing a user timing. The start time will be
+   * Get a timer object for reporting a user timing. The start time will be
    * the time that the object has been created, and the end time will be the
    * time that the "end" method is called on the object.
    */
@@ -99,7 +99,7 @@
   reportExecution(id: string, details: EventDetails): void;
   reportInteraction(eventName: string, details?: EventDetails): void;
   /**
-   * A draft interaction was started. Update the time-betweeen-draft-actions
+   * A draft interaction was started. Update the time-between-draft-actions
    * timer.
    */
   recordDraftInteraction(): void;
diff --git a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
index f80cb75..631a4e0 100644
--- a/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
+++ b/polygerrit-ui/app/services/gr-reporting/gr-reporting_impl.ts
@@ -292,17 +292,17 @@
 
   private readonly _baselines = STARTUP_TIMERS;
 
-  private _reportRepoName: string | undefined;
+  private reportRepoName: string | undefined;
 
-  private _reportChangeId: NumericChangeId | undefined;
+  private reportChangeId: NumericChangeId | undefined;
 
-  private _timers: {timeBetweenDraftActions: Timer | null} = {
+  private timers: {timeBetweenDraftActions: Timer | null} = {
     timeBetweenDraftActions: null,
   };
 
-  private _pending: PendingReportInfo[] = [];
+  private pending: PendingReportInfo[] = [];
 
-  private _slowRpcList: SlowRpcCall[] = [];
+  private slowRpcList: SlowRpcCall[] = [];
 
   /**
    * Keeps track of which ids were already reported to have been executed.
@@ -321,7 +321,7 @@
   }
 
   private get slowRpcSnapshot() {
-    return (this._slowRpcList || []).slice();
+    return (this.slowRpcList || []).slice();
   }
 
   private _arePluginsLoaded() {
@@ -366,16 +366,16 @@
     }
 
     // We report events immediately when metrics plugin is loaded
-    if (this._isMetricsPluginLoaded() && !this._pending.length) {
+    if (this._isMetricsPluginLoaded() && !this.pending.length) {
       this._reportEvent(eventInfo, noLog);
     } else {
       // We cache until metrics plugin is loaded
-      this._pending.push([eventInfo, noLog]);
+      this.pending.push([eventInfo, noLog]);
       if (this._isMetricsPluginLoaded()) {
-        this._pending.forEach(([eventInfo, opt_noLog]) => {
+        this.pending.forEach(([eventInfo, opt_noLog]) => {
           this._reportEvent(eventInfo, opt_noLog);
         });
-        this._pending = [];
+        this.pending = [];
       }
     }
   }
@@ -417,11 +417,11 @@
       eventInfo.eventDetails = JSON.stringify(eventDetails);
     }
 
-    if (this._reportRepoName) {
-      eventInfo.repoName = this._reportRepoName;
+    if (this.reportRepoName) {
+      eventInfo.repoName = this.reportRepoName;
     }
-    if (this._reportChangeId) {
-      eventInfo.changeId = `${this._reportChangeId}`;
+    if (this.reportChangeId) {
+      eventInfo.changeId = `${this.reportChangeId}`;
     }
 
     const isInBackgroundTab = document.visibilityState === 'hidden';
@@ -501,10 +501,10 @@
     this.time(TIMER.DIFF_VIEW_DISPLAYED);
     this.time(TIMER.DIFF_VIEW_LOAD_FULL);
     this.time(TIMER.FILE_LIST_DISPLAYED);
-    this._reportRepoName = undefined;
-    this._reportChangeId = undefined;
+    this.reportRepoName = undefined;
+    this.reportChangeId = undefined;
     // reset slow rpc list since here start page loads which report these rpcs
-    this._slowRpcList = [];
+    this.slowRpcList = [];
     this.hiddenDurationTimer.reset();
   }
 
@@ -651,7 +651,7 @@
     if (baseTime !== 0) {
       window.performance.measure(name, `${name}-start`);
     } else {
-      // Microsft Edge does not handle the 2nd param correctly
+      // Microsoft Edge does not handle the 2nd param correctly
       // (if undefined).
       window.performance.measure(name);
     }
@@ -659,7 +659,7 @@
 
   /**
    * Reports just line timeEnd, but additionally reports an average given a
-   * denominator and a separate reporiting name for the average.
+   * denominator and a separate reporting name for the average.
    *
    * @param name Timing name.
    * @param averageName Average timing name.
@@ -703,7 +703,7 @@
   }
 
   /**
-   * Get a timer object to for reporing a user timing. The start time will be
+   * Get a timer object to for reporting a user timing. The start time will be
    * the time that the object has been created, and the end time will be the
    * time that the "end" method is called on the object.
    */
@@ -765,7 +765,7 @@
       true
     );
     if (elapsed >= SLOW_RPC_THRESHOLD) {
-      this._slowRpcList.push({anonymizedUrl, elapsed});
+      this.slowRpcList.push({anonymizedUrl, elapsed});
     }
   }
 
@@ -805,17 +805,17 @@
   }
 
   /**
-   * A draft interaction was started. Update the time-betweeen-draft-actions
+   * A draft interaction was started. Update the time-between-draft-actions
    * timer.
    */
   recordDraftInteraction() {
     // If there is no timer defined, then this is the first interaction.
     // Set up the timer so that it's ready to record the intervening time when
     // called again.
-    const timer = this._timers.timeBetweenDraftActions;
+    const timer = this.timers.timeBetweenDraftActions;
     if (!timer) {
       // Create a timer with a maximum length.
-      this._timers.timeBetweenDraftActions = this.getTimer(
+      this.timers.timeBetweenDraftActions = this.getTimer(
         DRAFT_ACTION_TIMER
       ).withMaximum(DRAFT_ACTION_TIMER_MAX);
       return;
@@ -848,11 +848,11 @@
   }
 
   setRepoName(repoName: string) {
-    this._reportRepoName = repoName;
+    this.reportRepoName = repoName;
   }
 
   setChangeId(changeId: NumericChangeId) {
-    this._reportChangeId = changeId;
+    this.reportChangeId = changeId;
   }
 }
 
diff --git a/polygerrit-ui/app/styles/gr-voting-styles.ts b/polygerrit-ui/app/styles/gr-voting-styles.ts
index d4e6d52..c1989de 100644
--- a/polygerrit-ui/app/styles/gr-voting-styles.ts
+++ b/polygerrit-ui/app/styles/gr-voting-styles.ts
@@ -27,7 +27,7 @@
     <style>
       :host {
         --vote-chip-styles: {
-          border: 1px solid rgba(0,0,0,.12);
+          border: 1px solid var(--border-color);
           border-radius: 1em;
           box-shadow: none;
           box-sizing: border-box;
diff --git a/polygerrit-ui/app/styles/themes/app-theme.ts b/polygerrit-ui/app/styles/themes/app-theme.ts
index c3b0681..2d83cf5 100644
--- a/polygerrit-ui/app/styles/themes/app-theme.ts
+++ b/polygerrit-ui/app/styles/themes/app-theme.ts
@@ -101,6 +101,7 @@
     --tooltip-text-color: white;
     --negative-red-text-color: #d93025;
     --positive-green-text-color: #188038;
+    --indirect-ancestor-text-color: var(--green-700);
 
     /* background colors */
     /* primary background colors */
@@ -171,7 +172,7 @@
     --line-height-mono: 1.286rem;   /* 18px */
     --line-height-small: 1.143rem;  /* 16px */
     --line-height-normal: 1.429rem; /* 20px */
-    --line-height-h3: 1.714rem;     /* 24px */
+    --line-height-h3: 1.715rem;     /* 24px */
     --line-height-h2: 2rem;         /* 28px */
     --line-height-h1: 2.286rem;     /* 32px */
     --font-weight-normal: 400; /* 400 is the same as 'normal' */
diff --git a/polygerrit-ui/app/styles/themes/dark-theme.ts b/polygerrit-ui/app/styles/themes/dark-theme.ts
index 4057f7f..072ca8f 100644
--- a/polygerrit-ui/app/styles/themes/dark-theme.ts
+++ b/polygerrit-ui/app/styles/themes/dark-theme.ts
@@ -44,9 +44,12 @@
       --warning-background: var(--orange-900);
       --info-foreground: var(--blue-200);
       --info-background: var(--blue-900);
+      --selected-foreground: var(--blue-200);
+      --selected-background: var(--blue-900);
       --info-deemphasized-foreground: var(--gray-700);
       --info-deemphasized-background: var(--primary-text-color);
       --success-foreground: var(--green-200);
+      --success-background: var(--green-900);
       --gray-foreground: var(--gray-100);
       --gray-background: var(--gray-900);
       --tag-background: var(--cyan-900);
diff --git a/polygerrit-ui/app/tsconfig.json b/polygerrit-ui/app/tsconfig.json
index 0d751ab..46d0173d 100644
--- a/polygerrit-ui/app/tsconfig.json
+++ b/polygerrit-ui/app/tsconfig.json
@@ -48,7 +48,7 @@
   "include": [
     // Items below must be in sync with the src_dirs list in the BUILD file
     // Also items must be in sync with tsconfig_bazel.json, tsconfig_bazel_test.json
-    // (include and exclude arrays are overriden when extends)
+    // (include and exclude arrays are overridden when extends)
     "api/**/*",
     "constants/**/*",
     "elements/**/*",
diff --git a/polygerrit-ui/app/tsconfig_bazel.json b/polygerrit-ui/app/tsconfig_bazel.json
index 46bd926..dfd2078 100644
--- a/polygerrit-ui/app/tsconfig_bazel.json
+++ b/polygerrit-ui/app/tsconfig_bazel.json
@@ -9,7 +9,7 @@
   "include": [
     // Items below must be in sync with the src_dirs list in the BUILD file
     // Also items must be in sync with tsconfig.json, tsconfig_bazel_test.json
-    // (include and exclude arrays are overriden when extends)
+    // (include and exclude arrays are overridden when extends)
     "api/**/*",
     "constants/**/*",
     "elements/**/*",
diff --git a/polygerrit-ui/app/tsconfig_bazel_test.json b/polygerrit-ui/app/tsconfig_bazel_test.json
index 1b6c226..9c2ff93 100644
--- a/polygerrit-ui/app/tsconfig_bazel_test.json
+++ b/polygerrit-ui/app/tsconfig_bazel_test.json
@@ -14,7 +14,7 @@
   "include": [
     // Items below must be in sync with the src_dirs list in the BUILD file
     // Also items must be in sync with tsconfig.json, tsconfig_test.json
-    // (include and exclude arrays are overriden when extends)
+    // (include and exclude arrays are overridden when extends)
     "api/**/*",
     "constants/**/*",
     "elements/**/*",
diff --git a/polygerrit-ui/app/types/common.ts b/polygerrit-ui/app/types/common.ts
index 95801e7..711b11b 100644
--- a/polygerrit-ui/app/types/common.ts
+++ b/polygerrit-ui/app/types/common.ts
@@ -1021,7 +1021,7 @@
  */
 export interface PluginConfigInfo {
   has_avatars: boolean;
-  // The following 2 properies exists in Java class, but don't mention in docs
+  // The following 2 properties exists in Java class, but don't mention in docs
   js_resource_paths: string[];
   html_resource_paths: string[];
 }
diff --git a/polygerrit-ui/app/types/events.ts b/polygerrit-ui/app/types/events.ts
index 6b05fad..5965453 100644
--- a/polygerrit-ui/app/types/events.ts
+++ b/polygerrit-ui/app/types/events.ts
@@ -19,6 +19,7 @@
 import {UIComment} from '../utils/comment-util';
 import {FetchRequest} from './types';
 import {MovedLinkClickedEventDetail} from '../api/diff';
+import {Category, RunStatus} from '../api/checks';
 
 export interface TitleChangeEventDetail {
   title: string;
@@ -152,6 +153,7 @@
 
 export interface TabState {
   commentTab?: CommentTabState;
+  checksTab?: ChecksTabState;
 }
 
 export enum CommentTabState {
@@ -160,6 +162,11 @@
   SHOW_ALL = 'show all',
 }
 
+export interface ChecksTabState {
+  statusOrCategory?: RunStatus | Category;
+  checkName?: string;
+}
+
 export type SwitchTabEvent = CustomEvent<SwitchTabEventDetail>;
 
 declare global {
diff --git a/polygerrit-ui/app/utils/change-util.ts b/polygerrit-ui/app/utils/change-util.ts
index 1228863..a7f8b49 100644
--- a/polygerrit-ui/app/utils/change-util.ts
+++ b/polygerrit-ui/app/utils/change-util.ts
@@ -173,28 +173,44 @@
   return states;
 }
 
-export function isOwner(change?: ChangeInfo, account?: AccountInfo) {
+export function isOwner(change?: ChangeInfo, account?: AccountInfo): boolean {
   if (!change || !account) return false;
   return change.owner?._account_id === account._account_id;
 }
 
-export function isReviewer(change?: ChangeInfo, account?: AccountInfo) {
+export function isReviewer(
+  change?: ChangeInfo,
+  account?: AccountInfo
+): boolean {
   if (!change || !account) return false;
   const reviewers = change.reviewers.REVIEWER ?? [];
   return reviewers.some(r => r._account_id === account._account_id);
 }
 
-export function isUploader(change?: ChangeInfo, account?: AccountInfo) {
+export function isCc(change?: ChangeInfo, account?: AccountInfo): boolean {
+  if (!change || !account) return false;
+  const ccs = change.reviewers.CC ?? [];
+  return ccs.some(r => r._account_id === account._account_id);
+}
+
+export function isUploader(
+  change?: ChangeInfo,
+  account?: AccountInfo
+): boolean {
   if (!change || !account) return false;
   const rev = getCurrentRevision(change);
   return rev?.uploader?._account_id === account._account_id;
 }
 
-export function isInvolved(change?: ChangeInfo, account?: AccountInfo) {
+export function isInvolved(
+  change?: ChangeInfo,
+  account?: AccountInfo
+): boolean {
   const owner = isOwner(change, account);
   const uploader = isUploader(change, account);
   const reviewer = isReviewer(change, account);
-  return owner || uploader || reviewer;
+  const cc = isCc(change, account);
+  return owner || uploader || reviewer || cc;
 }
 
 export function getCurrentRevision(change?: ChangeInfo) {
diff --git a/polygerrit-ui/app/utils/common-util.ts b/polygerrit-ui/app/utils/common-util.ts
index 2246251..f4d6d51 100644
--- a/polygerrit-ui/app/utils/common-util.ts
+++ b/polygerrit-ui/app/utils/common-util.ts
@@ -111,3 +111,14 @@
   }
   return true;
 }
+
+/**
+ * Add value, if the set does not contain it. Otherwise remove it.
+ */
+export function toggleSetMembership<T>(set: Set<T>, value: T): void {
+  if (set.has(value)) {
+    set.delete(value);
+  } else {
+    set.add(value);
+  }
+}
diff --git a/polygerrit-ui/app/utils/common-util_test.js b/polygerrit-ui/app/utils/common-util_test.js
index 917d652b..d6d66d7 100644
--- a/polygerrit-ui/app/utils/common-util_test.js
+++ b/polygerrit-ui/app/utils/common-util_test.js
@@ -29,7 +29,7 @@
       assert.isTrue(hasOwnProperty(obj, 'name with spaces'));
       assert.isFalse(hasOwnProperty(obj, 'def'));
     });
-    test('object prototype has overriden hasOwnProperty', () => {
+    test('object prototype has overridden hasOwnProperty', () => {
       const F = function() {
         this.abc = 23;
       };
diff --git a/polygerrit-ui/app/utils/dom-util.ts b/polygerrit-ui/app/utils/dom-util.ts
index aa83173..7f9ef72 100644
--- a/polygerrit-ui/app/utils/dom-util.ts
+++ b/polygerrit-ui/app/utils/dom-util.ts
@@ -16,6 +16,7 @@
  */
 
 import {EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
+import {check} from './common-util';
 
 /**
  * Event emitted from polymer elements.
@@ -155,7 +156,7 @@
 
 export function windowLocationReload() {
   const e = new Error();
-  console.info(`Calling window.location.realod(): ${e.stack}`);
+  console.info(`Calling window.location.reload(): ${e.stack}`);
   window.location.reload();
 }
 
@@ -258,3 +259,22 @@
     (/iPad|iPhone|iPod/.test(navigator.userAgent) && !window.MSStream)
   );
 }
+
+export function whenVisible(
+  element: Element,
+  callback: () => void,
+  marginPx = 0
+) {
+  const observer = new IntersectionObserver(
+    (entries: IntersectionObserverEntry[]) => {
+      check(entries.length === 1, 'Expected one intersection observer entry.');
+      const entry = entries[0];
+      if (entry.isIntersecting) {
+        observer.unobserve(entry.target);
+        callback();
+      }
+    },
+    {rootMargin: `${marginPx}px`}
+  );
+  observer.observe(element);
+}
diff --git a/polygerrit-ui/app/utils/label-util.ts b/polygerrit-ui/app/utils/label-util.ts
index 60ac4d8..4eed0a0 100644
--- a/polygerrit-ui/app/utils/label-util.ts
+++ b/polygerrit-ui/app/utils/label-util.ts
@@ -51,3 +51,11 @@
 ): ApprovalInfo | undefined {
   return label.all?.filter(x => x._account_id === account._account_id)[0];
 }
+
+export function labelCompare(labelName1: string, labelName2: string) {
+  if (labelName1 === CODE_REVIEW && labelName2 === CODE_REVIEW) return 0;
+  if (labelName1 === CODE_REVIEW) return -1;
+  if (labelName2 === CODE_REVIEW) return 1;
+
+  return labelName1.localeCompare(labelName2);
+}
diff --git a/polygerrit-ui/app/utils/label-util_test.js b/polygerrit-ui/app/utils/label-util_test.js
index 6a2f768..f9a30df 100644
--- a/polygerrit-ui/app/utils/label-util_test.js
+++ b/polygerrit-ui/app/utils/label-util_test.js
@@ -21,6 +21,7 @@
   getVotingRangeOrDefault,
   getMaxAccounts,
   getApprovalInfo,
+  labelCompare,
 } from './label-util.js';
 
 const VALUES_1 = {
@@ -113,4 +114,11 @@
     };
     assert.isUndefined(getApprovalInfo(label, myAccountInfo));
   });
+
+  test('labelCompare', () => {
+    let sorted = ['c', 'b', 'a'].sort(labelCompare);
+    assert.sameOrderedMembers(sorted, ['a', 'b', 'c']);
+    sorted = ['b', 'a', 'Code-Review'].sort(labelCompare);
+    assert.sameOrderedMembers(sorted, ['Code-Review', 'a', 'b']);
+  });
 });
diff --git a/polygerrit-ui/app/utils/url-util_test.js b/polygerrit-ui/app/utils/url-util_test.js
index 0658be3..b1b17f4 100644
--- a/polygerrit-ui/app/utils/url-util_test.js
+++ b/polygerrit-ui/app/utils/url-util_test.js
@@ -25,15 +25,15 @@
 
 suite('url-util tests', () => {
   suite('getBaseUrl tests', () => {
-    let originialCanonicalPath;
+    let originalCanonicalPath;
 
     suiteSetup(() => {
-      originialCanonicalPath = window.CANONICAL_PATH;
+      originalCanonicalPath = window.CANONICAL_PATH;
       window.CANONICAL_PATH = '/r';
     });
 
     suiteTeardown(() => {
-      window.CANONICAL_PATH = originialCanonicalPath;
+      window.CANONICAL_PATH = originalCanonicalPath;
     });
 
     test('getBaseUrl', () => {
diff --git a/polygerrit-ui/app/yarn.lock b/polygerrit-ui/app/yarn.lock
index e544dbc..ec3b7a0 100644
--- a/polygerrit-ui/app/yarn.lock
+++ b/polygerrit-ui/app/yarn.lock
@@ -324,6 +324,11 @@
   dependencies:
     "@webcomponents/shadycss" "^1.9.1"
 
+"@types/resize-observer-browser@^0.1.5":
+  version "0.1.5"
+  resolved "https://registry.yarnpkg.com/@types/resize-observer-browser/-/resize-observer-browser-0.1.5.tgz#36d897708172ac2380cd486da7a3daf1161c1e23"
+  integrity sha512-8k/67Z95Goa6Lznuykxkfhq9YU3l1Qe6LNZmwde1u7802a3x8v44oq0j91DICclxatTr0rNnhXx7+VTIetSrSQ==
+
 "@webcomponents/shadycss@^1.9.1", "@webcomponents/shadycss@^1.9.2":
   version "1.9.4"
   resolved "https://registry.yarnpkg.com/@webcomponents/shadycss/-/shadycss-1.9.4.tgz#4f9d8ea1526bab084c60b53d4854dc39fdb2bb48"