diff --git a/Documentation/dev-e2e-tests.txt b/Documentation/dev-e2e-tests.txt
index 012a731..86221eb 100644
--- a/Documentation/dev-e2e-tests.txt
+++ b/Documentation/dev-e2e-tests.txt
@@ -18,7 +18,9 @@
 to run tests at Git protocol level.
 
 Gatling is written in Scala, but the abstraction provided by the Gatling DSL makes the scenarios
-implementation easy even without any Scala knowledge.
+implementation easy even without any Scala knowledge. The
+link:https://gitenterprise.me/2019/12/20/stress-your-gerrit-with-gatling/[Stress your Gerrit with Gatling]
+blog post has more introductory information.
 
 Examples of scenarios can be found in the `e2e-tests` directory. The files in that directory
 should be formatted using the mainstream
diff --git a/Documentation/dev-plugins.txt b/Documentation/dev-plugins.txt
index 9714e18..3266cb1 100644
--- a/Documentation/dev-plugins.txt
+++ b/Documentation/dev-plugins.txt
@@ -476,9 +476,9 @@
 ----
 
 Plugins which define new Events should register them via the
-`com.google.gerrit.server.events.EventTypes.registerClass()`
-method. This will make the EventType known to the system.
-Deserializing events with the
+`com.google.gerrit.server.events.EventTypes.register()` method.
+This will make the EventType known to the system. Deserializing
+events with the
 `com.google.gerrit.server.events.EventDeserializer` class requires
 that the event be registered in EventTypes.
 
diff --git a/e2e-tests/load-tests/project/build.properties b/e2e-tests/load-tests/project/build.properties
index 0cd8b07..a82bb05 100644
--- a/e2e-tests/load-tests/project/build.properties
+++ b/e2e-tests/load-tests/project/build.properties
@@ -1 +1 @@
-sbt.version=1.2.3
+sbt.version=1.3.7
diff --git a/e2e-tests/load-tests/src/test/resources/data/requests.json b/e2e-tests/load-tests/src/test/resources/data/ReplayRecordsFromFeeder.json
similarity index 100%
rename from e2e-tests/load-tests/src/test/resources/data/requests.json
rename to e2e-tests/load-tests/src/test/resources/data/ReplayRecordsFromFeeder.json
diff --git a/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/CloneUsingBothProtocols.scala b/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/CloneUsingBothProtocols.scala
index b02657a..9e2aca0 100644
--- a/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/CloneUsingBothProtocols.scala
+++ b/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/CloneUsingBothProtocols.scala
@@ -44,8 +44,8 @@
 
   setUp(
     test.inject(
-      constantUsersPerSec(1) during (2 seconds))
-  ).protocols(protocol)
+      constantUsersPerSec(1) during (2 seconds)
+    )).protocols(protocol)
 
   after {
     Thread.sleep(5000)
diff --git a/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/ReplayRecordsFromFeeder.scala b/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/ReplayRecordsFromFeeder.scala
index c0eab39..5a3bb99 100644
--- a/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/ReplayRecordsFromFeeder.scala
+++ b/e2e-tests/load-tests/src/test/scala/com/google/gerrit/scenarios/ReplayRecordsFromFeeder.scala
@@ -14,59 +14,55 @@
 
 package com.google.gerrit.scenarios
 
-import com.github.barbasa.gatling.git.protocol.GitProtocol
-import com.github.barbasa.gatling.git.request.builder.GitRequestBuilder
-import io.gatling.core.Predef._
-import io.gatling.core.structure.ScenarioBuilder
 import java.io._
 
-import com.github.barbasa.gatling.git.{
-  GatlingGitConfiguration,
-  GitRequestSession
-}
+import com.github.barbasa.gatling.git.protocol.GitProtocol
+import com.github.barbasa.gatling.git.request.builder.GitRequestBuilder
+import com.github.barbasa.gatling.git.{GatlingGitConfiguration, GitRequestSession}
+import io.gatling.core.Predef._
+import io.gatling.core.feeder.FileBasedFeederBuilder
+import io.gatling.core.structure.ScenarioBuilder
 import org.apache.commons.io.FileUtils
-
-import scala.concurrent.duration._
 import org.eclipse.jgit.hooks._
 
-class ReplayRecordsFromFeederScenario extends Simulation {
+import scala.concurrent.duration._
 
-  val gitProtocol = GitProtocol()
-  implicit val conf = GatlingGitConfiguration()
-  implicit val postMessageHook: Option[String] = Some(
-    s"hooks/${CommitMsgHook.NAME}")
+class ReplayRecordsFromFeeder extends Simulation {
 
-  val feeder = jsonFile("data/requests.json").circular
+  implicit val conf: GatlingGitConfiguration = GatlingGitConfiguration()
+  implicit val postMessageHook: Option[String] = Some(s"hooks/${CommitMsgHook.NAME}")
 
-  val replayCallsScenario: ScenarioBuilder =
-    scenario("Git commands")
+  private val name: String = this.getClass.getSimpleName
+  private val file = s"data/$name.json"
+  private val data: FileBasedFeederBuilder[Any]#F = jsonFile(file).circular
+  private val request = new GitRequestBuilder(GitRequestSession("${cmd}", "${url}"))
+  private val protocol: GitProtocol = GitProtocol()
+
+  private val test: ScenarioBuilder = scenario(name)
       .repeat(10000) {
-        feed(feeder)
-          .exec(new GitRequestBuilder(GitRequestSession("${cmd}", "${url}")))
+        feed(data)
+            .exec(request)
       }
 
   setUp(
-    replayCallsScenario.inject(
+    test.inject(
       nothingFor(4 seconds),
       atOnceUsers(10),
       rampUsers(10) during (5 seconds),
       constantUsersPerSec(20) during (15 seconds),
       constantUsersPerSec(20) during (15 seconds) randomized
-    ))
-    .protocols(gitProtocol)
-    .maxDuration(60 seconds)
+    )).protocols(protocol)
+      .maxDuration(60 seconds)
 
   after {
+    Thread.sleep(5000)
+    val path = conf.tmpBasePath
     try {
-      //After is often called too early. Some retries should be implemented.
-      Thread.sleep(5000)
-      FileUtils.deleteDirectory(new File(conf.tmpBasePath))
+      FileUtils.deleteDirectory(new File(path))
     } catch {
-      case e: IOException => {
-        System.err.println(
-          "Unable to delete temporary directory: " + conf.tmpBasePath)
-        e.printStackTrace
-      }
+      case e: IOException =>
+        System.err.println("Unable to delete temporary directory " + path)
+        e.printStackTrace()
     }
   }
 }
diff --git a/java/com/google/gerrit/extensions/systemstatus/MessageOfTheDay.java b/java/com/google/gerrit/extensions/systemstatus/MessageOfTheDay.java
deleted file mode 100644
index 180a0e6..0000000
--- a/java/com/google/gerrit/extensions/systemstatus/MessageOfTheDay.java
+++ /dev/null
@@ -1,63 +0,0 @@
-// Copyright (C) 2014 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.extensions.systemstatus;
-
-import com.google.gerrit.extensions.annotations.ExtensionPoint;
-import java.util.Calendar;
-import java.util.Date;
-import java.util.TimeZone;
-
-/**
- * Supplies a message of the day when the page is first loaded.
- *
- * <pre>
- * DynamicSet.bind(binder(), MessageOfTheDay.class).to(MyMessage.class);
- * </pre>
- */
-@ExtensionPoint
-public abstract class MessageOfTheDay {
-  /**
-   * Retrieve the message of the day as an HTML fragment.
-   *
-   * @return message as an HTML fragment; null if no message is available.
-   */
-  public abstract String getHtmlMessage();
-
-  /**
-   * Unique identifier for this message.
-   *
-   * <p>Messages with the same identifier will be hidden from the user until redisplay has occurred.
-   *
-   * @return unique message identifier. This identifier should be unique within the server.
-   */
-  public abstract String getMessageId();
-
-  /**
-   * When should the message be displayed?
-   *
-   * <p>Default implementation returns {@code tomorrow at 00:00:00 GMT}.
-   *
-   * @return a future date after which the message should be redisplayed.
-   */
-  public Date getRedisplay() {
-    Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
-    cal.set(Calendar.HOUR_OF_DAY, 0);
-    cal.set(Calendar.MINUTE, 0);
-    cal.set(Calendar.SECOND, 0);
-    cal.set(Calendar.MILLISECOND, 0);
-    cal.add(Calendar.DAY_OF_MONTH, 1);
-    return cal.getTime();
-  }
-}
diff --git a/java/com/google/gerrit/metrics/proc/JGitMetricModule.java b/java/com/google/gerrit/metrics/proc/JGitMetricModule.java
index 438f70e..3819786 100644
--- a/java/com/google/gerrit/metrics/proc/JGitMetricModule.java
+++ b/java/com/google/gerrit/metrics/proc/JGitMetricModule.java
@@ -28,12 +28,12 @@
         new Description("Bytes of memory retained in JGit block cache.")
             .setGauge()
             .setUnit(Units.BYTES),
-        WindowCacheStats::getOpenBytes);
+        () -> WindowCacheStats.getStats().getOpenByteCount());
 
     metrics.newCallbackMetric(
         "jgit/block_cache/open_files",
-        Integer.class,
+        Long.class,
         new Description("File handles held open by JGit block cache.").setGauge().setUnit("fds"),
-        WindowCacheStats::getOpenFiles);
+        () -> WindowCacheStats.getStats().getOpenFileCount());
   }
 }
diff --git a/java/com/google/gerrit/server/config/GerritGlobalModule.java b/java/com/google/gerrit/server/config/GerritGlobalModule.java
index 012e4cd..3914205 100644
--- a/java/com/google/gerrit/server/config/GerritGlobalModule.java
+++ b/java/com/google/gerrit/server/config/GerritGlobalModule.java
@@ -61,7 +61,6 @@
 import com.google.gerrit.extensions.registration.DynamicItem;
 import com.google.gerrit.extensions.registration.DynamicMap;
 import com.google.gerrit.extensions.registration.DynamicSet;
-import com.google.gerrit.extensions.systemstatus.MessageOfTheDay;
 import com.google.gerrit.extensions.validators.CommentValidator;
 import com.google.gerrit.extensions.webui.BranchWebLink;
 import com.google.gerrit.extensions.webui.DiffWebLink;
@@ -365,7 +364,6 @@
     DynamicItem.itemOf(binder(), AvatarProvider.class);
     DynamicSet.setOf(binder(), LifecycleListener.class);
     DynamicSet.setOf(binder(), TopMenu.class);
-    DynamicSet.setOf(binder(), MessageOfTheDay.class);
     DynamicMap.mapOf(binder(), DownloadScheme.class);
     DynamicMap.mapOf(binder(), DownloadCommand.class);
     DynamicMap.mapOf(binder(), CloneCommand.class);
diff --git a/java/com/google/gerrit/server/restapi/config/GetSummary.java b/java/com/google/gerrit/server/restapi/config/GetSummary.java
index 1df485f..d0a1498 100644
--- a/java/com/google/gerrit/server/restapi/config/GetSummary.java
+++ b/java/com/google/gerrit/server/restapi/config/GetSummary.java
@@ -126,8 +126,8 @@
     long mTotal = r.totalMemory();
     long mInuse = mTotal - mFree;
 
-    int jgitOpen = WindowCacheStats.getOpenFiles();
-    long jgitBytes = WindowCacheStats.getOpenBytes();
+    long jgitOpen = WindowCacheStats.getStats().getOpenFileCount();
+    long jgitBytes = WindowCacheStats.getStats().getOpenByteCount();
 
     MemSummaryInfo memSummaryInfo = new MemSummaryInfo();
     memSummaryInfo.total = bytes(mTotal);
@@ -135,7 +135,7 @@
     memSummaryInfo.free = bytes(mFree);
     memSummaryInfo.buffers = bytes(jgitBytes);
     memSummaryInfo.max = bytes(mMax);
-    memSummaryInfo.openFiles = toInteger(jgitOpen);
+    memSummaryInfo.openFiles = Long.valueOf(jgitOpen);
     return memSummaryInfo;
   }
 
@@ -258,7 +258,7 @@
     public String free;
     public String buffers;
     public String max;
-    public Integer openFiles;
+    public Long openFiles;
   }
 
   public static class ThreadSummaryInfo {
diff --git a/java/com/google/gerrit/sshd/commands/ShowCaches.java b/java/com/google/gerrit/sshd/commands/ShowCaches.java
index 7e0439f..1d756de 100644
--- a/java/com/google/gerrit/sshd/commands/ShowCaches.java
+++ b/java/com/google/gerrit/sshd/commands/ShowCaches.java
@@ -297,6 +297,10 @@
     return i != null ? i : 0;
   }
 
+  private static long nullToZero(Long i) {
+    return i != null ? i : 0;
+  }
+
   private void sshSummary() {
     IoAcceptor acceptor = daemon.getIoAcceptor();
     if (acceptor == null) {
diff --git a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
index cdffa3c..9624ec2 100644
--- a/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
+++ b/javatests/com/google/gerrit/acceptance/rest/change/AbstractSubmit.java
@@ -57,7 +57,6 @@
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.data.Permission;
 import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.BooleanProjectConfig;
 import com.google.gerrit.entities.BranchNameKey;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.PatchSet;
@@ -645,14 +644,7 @@
     //  |
     // C0 -- Master
     //
-    try (ProjectConfigUpdate u = updateProject(project)) {
-      u.getConfig()
-          .getProject()
-          .setBooleanConfig(
-              BooleanProjectConfig.CREATE_NEW_CHANGE_FOR_ALL_NOT_IN_TARGET,
-              InheritableBoolean.TRUE);
-      u.save();
-    }
+    enableCreateNewChangeForAllNotInTarget();
 
     PushOneCommit push1 =
         pushFactory.create(admin.newIdent(), testRepo, PushOneCommit.SUBJECT, "a.txt", "content");
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
index 0e86746..11e2217 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.html
@@ -353,6 +353,9 @@
           z-index: var(--reply-overlay-z-index);
         }
       }
+      .patch-set-dropdown {
+        margin: var(--spacing-m) 0 0 var(--spacing-m);
+      }
     </style>
     <div class="container loading" hidden$="[[!_loading]]">Loading...</div>
     <div
@@ -640,6 +643,12 @@
       </template>
       <template is="dom-if" if="[[_isSelectedView(_currentView,
         _commentTabs.ROBOT_COMMENTS)]]">
+        <gr-dropdown-list
+          class="patch-set-dropdown"
+          items="[[_robotCommentsPatchSetDropdownItems]]"
+          on-value-change="_handleRobotCommentPatchSetChanged"
+          value="[[_currentRobotCommentsPatchSet]]">
+        </gr-dropdown-list>
         <gr-thread-list
             threads="[[_robotCommentThreads]]"
             change="[[_change]]"
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
index 124d10b..d2f8c87 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.js
@@ -141,7 +141,7 @@
         _robotCommentThreads: {
           type: Array,
           computed: '_computeRobotCommentThreads(_commentThreads,'
-            + ' _selectedRevision)',
+            + ' _currentRobotCommentsPatchSet)',
         },
         /** @type {?} */
         _serverConfig: {
@@ -181,6 +181,7 @@
           type: Object,
           computed: '_computeCurrentRevision(_change.current_revision, ' +
             '_change.revisions)',
+          observer: '_handleCurrentRevisionUpdate',
         },
         _files: Object,
         _changeNum: String,
@@ -318,6 +319,14 @@
         _selectedFilesTabPluginEndpoint: {
           type: String,
         },
+        _robotCommentsPatchSetDropdownItems: {
+          type: Array,
+          value() { return []; },
+          computed: '_computeRobotCommentsPatchSetDropdownItems(_change)',
+        },
+        _currentRobotCommentsPatchSet: {
+          type: Number,
+        },
       };
     }
 
@@ -584,12 +593,35 @@
       return false;
     }
 
-    _computeRobotCommentThreads(commentThreads, selectedRevision) {
-      if (!commentThreads || !selectedRevision) return [];
+    _computeRobotCommentsPatchSetDropdownItems(change) {
+      if (!change.revisions) return [];
+      return Object.values(change.revisions)
+          .filter(patch => patch._number !== 'edit')
+          .map(patch => {
+            return {
+              text: 'Patchset ' + patch._number,
+              value: patch._number,
+            };
+          })
+          .sort((a, b) => b.value - a.value);
+    }
+
+    _handleCurrentRevisionUpdate(currentRevision) {
+      this._currentRobotCommentsPatchSet = currentRevision._number;
+    }
+
+    _handleRobotCommentPatchSetChanged(e) {
+      const patchSet = parseInt(e.detail.value);
+      if (patchSet === this._currentRobotCommentsPatchSet) return;
+      this._currentRobotCommentsPatchSet = patchSet;
+    }
+
+    _computeRobotCommentThreads(commentThreads, currentRobotCommentsPatchSet) {
+      if (!commentThreads || !currentRobotCommentsPatchSet) return [];
       return commentThreads.filter(thread => {
         const comments = thread.comments || [];
         return comments.length && comments[0].robot_id && (comments[0].patch_set
-          === selectedRevision._number);
+          === currentRobotCommentsPatchSet);
       });
     }
 
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
index 7224278..f0ab218 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view_test.html
@@ -662,8 +662,18 @@
 
     suite('Findings comment tab', () => {
       setup(done => {
+        element._change = {
+          change_id: 'Iad9dc96274af6946f3632be53b106ef80f7ba6ca',
+          revisions: {
+            rev2: {_number: 2, commit: {parents: []}},
+            rev1: {_number: 1, commit: {parents: []}},
+            rev13: {_number: 13, commit: {parents: []}},
+            rev3: {_number: 3, commit: {parents: []}},
+            rev4: {_number: 4, commit: {parents: []}},
+          },
+          current_revision: 'rev4',
+        };
         element._commentThreads = THREADS;
-        element._selectedRevision = {_number: 4};
         flush(() => {
           done();
         });
@@ -676,7 +686,7 @@
             'rc2');
       });
       test('changing patchsets resets robot comments', done => {
-        element._selectedRevision = {_number: 3};
+        element.set('_change.current_revision', 'rev3');
         flush(() => {
           assert.equal(element._robotCommentThreads.length, 0);
           done();
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.html b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.html
index 1a1276d..a845ed4 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.html
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.html
@@ -16,12 +16,15 @@
 -->
 
 <link rel="import" href="/bower_components/polymer/polymer.html">
+<link rel="import" href="/bower_components/iron-icon/iron-icon.html">
 
+<link rel="import" href="../../shared/gr-icons/gr-icons.html">
 <link rel="import" href="../../core/gr-navigation/gr-navigation.html">
 <link rel="import" href="../../shared/gr-dialog/gr-dialog.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
 <link rel="import" href="../../plugins/gr-endpoint-decorator/gr-endpoint-decorator.html">
 <link rel="import" href="../../plugins/gr-endpoint-param/gr-endpoint-param.html">
+
 <link rel="import" href="../../../styles/shared-styles.html">
 
 <dom-module id="gr-confirm-submit-dialog">
@@ -33,6 +36,11 @@
       p {
         margin-bottom: var(--spacing-l);
       }
+      .warningBeforeSubmit {
+        color: var(--error-text-color);
+        vertical-align: top;
+        margin-right: var(--spacing-s);
+      }
       @media screen and (max-width: 50em) {
         #dialog {
           min-width: inherit;
@@ -53,7 +61,17 @@
         <gr-endpoint-decorator name="confirm-submit-change">
           <p>Ready to submit &ldquo;<strong>[[change.subject]]</strong>&rdquo;?</p>
           <template is="dom-if" if="[[change.is_private]]">
-            <p><strong>Heads Up!</strong> Submitting this private change will also make it public.</p>
+            <p>
+              <iron-icon icon="gr-icons:error" class="warningBeforeSubmit"></iron-icon>
+              <strong>Heads Up!</strong>
+              Submitting this private change will also make it public.
+            </p>
+          </template>
+          <template is="dom-if" if="[[change.unresolved_comment_count]]">
+            <p>
+              <iron-icon icon="gr-icons:error" class="warningBeforeSubmit"></iron-icon>
+              [[_computeUnresolvedCommentsWarning(change)]]
+            </p>
           </template>
           <gr-endpoint-param name="change" value="[[change]]"></gr-endpoint-param>
           <gr-endpoint-param name="action" value="[[action]]"></gr-endpoint-param>
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.js b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.js
index ea8bdb5..aa26681 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog.js
@@ -57,6 +57,12 @@
       this.$.dialog.resetFocus();
     }
 
+    _computeUnresolvedCommentsWarning(change) {
+      const unresolvedCount = change.unresolved_comment_count;
+      const plural = unresolvedCount > 1 ? 's' : '';
+      return `Heads Up! ${unresolvedCount} unresolved comment${plural}.`;
+    }
+
     _handleConfirmTap(e) {
       e.preventDefault();
       e.stopPropagation();
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_test.html b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_test.html
index 515147f..2ae58af 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_test.html
+++ b/polygerrit-ui/app/elements/change/gr-confirm-submit-dialog/gr-confirm-submit-dialog_test.html
@@ -61,5 +61,15 @@
       assert.notEqual(message.textContent.length, 0);
       assert.notEqual(message.textContent.indexOf('my-subject'), -1);
     });
+
+    test('_computeUnresolvedCommentsWarning', () => {
+      const change = {unresolved_comment_count: 1};
+      assert.equal(element._computeUnresolvedCommentsWarning(change),
+          'Heads Up! 1 unresolved comment.');
+
+      const change2 = {unresolved_comment_count: 2};
+      assert.equal(element._computeUnresolvedCommentsWarning(change2),
+          'Heads Up! 2 unresolved comments.');
+    });
   });
 </script>
diff --git a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.html b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.html
index 46fd227..134dd5c 100644
--- a/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.html
+++ b/polygerrit-ui/app/elements/change/gr-label-score-row/gr-label-score-row.html
@@ -27,42 +27,37 @@
       /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
     </style>
     <style include="shared-styles">
-      .labelContainer {
-        align-items: center;
-        display: flex;
-        margin-bottom: var(--spacing-m);
+      .labelNameCell,
+      .buttonsCell,
+      .selectedValueCell {
+        padding: var(--spacing-s) var(--spacing-m);
+        display: table-cell;
       }
-      .labelName {
-        display: inline-block;
-        flex: 0 0 auto;
-        margin-right: var(--spacing-m);
-        min-width: 7em;
-        text-align: left;
-        width: 20%;
+      /* We want the :hover highlight to extend to the border of the dialog. */
+      .labelNameCell {
+        padding-left: var(--spacing-xl);
+      }
+      .selectedValueCell {
+        padding-right: var(--spacing-xl);
+      }
+      /* This is a trick to let the selectedValueCell take the remaining width. */
+      .labelNameCell,
+      .buttonsCell {
+        white-space: nowrap;
+      }
+      .selectedValueCell {
+        width: 75%;
       }
       .labelMessage {
         color: var(--deemphasized-text-color);
       }
-      .placeholder::before {
-        content: ' ';
-      }
-      .selectedValueText {
-        color: var(--deemphasized-text-color);
-        font-style: italic;
-        margin: 0 var(--spacing-m);
-      }
-      .selectedValueText.hidden {
-        display: none;
-      }
-      .buttonWrapper {
-        flex: none;
-      }
       gr-button {
-        min-width: 40px;
+        min-width: 42px;
+        box-sizing: border-box;
         --gr-button: {
           background-color: var(--button-background-color, var(--table-header-background-color));
           color: var(--primary-text-color);
-          padding: var(--spacing-xs) var(--spacing-m);
+          padding: 0 var(--spacing-m);
           @apply --vote-chip-styles;
         }
       }
@@ -83,63 +78,62 @@
       }
       .placeholder {
         display: inline-block;
-        width: 40px;
+        width: 42px;
+        height: 1px;
+      }
+      .placeholder::before {
+        content: ' ';
+      }
+      .selectedValueCell {
+        color: var(--deemphasized-text-color);
+        font-style: italic;
+      }
+      .selectedValueCell.hidden {
+        display: none;
       }
       @media only screen and (max-width: 50em) {
-        .selectedValueText {
+        .selectedValueCell {
           display: none;
         }
       }
-      @media only screen and (max-width: 25em) {
-        .labelName {
-          margin: 0;
-          text-align: center;
-          width: 100%;
-        }
-        .labelContainer {
-          display: block;
-        }
-      }
     </style>
-    <div class="labelContainer">
-      <span class="labelName">[[label.name]]</span>
-      <div class="buttonWrapper">
+    <span class="labelNameCell">[[label.name]]</span>
+    <div class="buttonsCell">
+      <template is="dom-repeat"
+          items="[[_computeBlankItems(permittedLabels, label.name, 'start')]]"
+          as="value">
+        <span class="placeholder" data-label$="[[label.name]]"></span>
+      </template>
+      <iron-selector
+          id="labelSelector"
+          attr-for-selected="data-value"
+          selected="[[_computeLabelValue(labels, permittedLabels, label)]]"
+          hidden$="[[!_computeAnyPermittedLabelValues(permittedLabels, label.name)]]"
+          on-selected-item-changed="_setSelectedValueText">
         <template is="dom-repeat"
-            items="[[_computeBlankItems(permittedLabels, label.name, 'start')]]"
+            items="[[_items]]"
             as="value">
-          <span class="placeholder" data-label$="[[label.name]]"></span>
+          <gr-button
+              class$="[[_computeButtonClass(value, index, _items.length)]]"
+              has-tooltip
+              data-name$="[[label.name]]"
+              data-value$="[[value]]"
+              title$="[[_computeLabelValueTitle(labels, label.name, value)]]">
+            [[value]]</gr-button>
         </template>
-        <iron-selector
-            id="labelSelector"
-            attr-for-selected="data-value"
-            selected="[[_computeLabelValue(labels, permittedLabels, label)]]"
-            hidden$="[[!_computeAnyPermittedLabelValues(permittedLabels, label.name)]]"
-            on-selected-item-changed="_setSelectedValueText">
-          <template is="dom-repeat"
-              items="[[_items]]"
-              as="value">
-            <gr-button
-                class$="[[_computeButtonClass(value, index, _items.length)]]"
-                has-tooltip
-                data-name$="[[label.name]]"
-                data-value$="[[value]]"
-                title$="[[_computeLabelValueTitle(labels, label.name, value)]]">
-              [[value]]</gr-button>
-          </template>
-        </iron-selector>
-        <template is="dom-repeat"
-            items="[[_computeBlankItems(permittedLabels, label.name, 'end')]]"
-            as="value">
-          <span class="placeholder" data-label$="[[label.name]]"></span>
-        </template>
-        <span class="labelMessage"
-            hidden$="[[_computeAnyPermittedLabelValues(permittedLabels, label.name)]]">
-          You don't have permission to edit this label.
-        </span>
-      </div>
-      <div class$="selectedValueText [[_computeHiddenClass(permittedLabels, label.name)]]">
-        <span id="selectedValueLabel">[[_selectedValueText]]</span>
-      </div>
+      </iron-selector>
+      <template is="dom-repeat"
+          items="[[_computeBlankItems(permittedLabels, label.name, 'end')]]"
+          as="value">
+        <span class="placeholder" data-label$="[[label.name]]"></span>
+      </template>
+      <span class="labelMessage"
+          hidden$="[[_computeAnyPermittedLabelValues(permittedLabels, label.name)]]">
+        You don't have permission to edit this label.
+      </span>
+    </div>
+    <div class$="selectedValueCell [[_computeHiddenClass(permittedLabels, label.name)]]">
+      <span id="selectedValueLabel">[[_selectedValueText]]</span>
     </div>
   </template>
   <script src="gr-label-score-row.js"></script>
diff --git a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.html b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.html
index c607a9f..29b83a3 100644
--- a/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.html
+++ b/polygerrit-ui/app/elements/change/gr-label-scores/gr-label-scores.html
@@ -23,18 +23,23 @@
 <dom-module id="gr-label-scores">
   <template>
     <style include="shared-styles">
+      :host {
+        display: table;
+        width: 100%;
+      }
       .mergedMessage {
         font-style: italic;
         text-align: center;
         width: 100%;
       }
-      gr-label-score-row.no-access {
-        display: var(--label-no-access-display, initial);
+      gr-label-score-row:hover {
+        background-color: var(--hover-background-color);
       }
-      @media only screen and (max-width: 25em) {
-        :host {
-          text-align: center;
-        }
+      gr-label-score-row {
+        display: table-row;
+      }
+      gr-label-score-row.no-access {
+        display: var(--label-no-access-display, table-row);
       }
     </style>
     <template is="dom-repeat" items="[[_labels]]" as="label">
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.html b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
index e77bf57..2ea1134 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.html
@@ -156,6 +156,9 @@
       .commentsIcon {
         vertical-align: top;
       }
+      .score.removed {
+        background-color: var(--vote-color-neutral);
+      }
       .score.negative {
         background-color: var(--vote-color-disliked);
       }
@@ -195,7 +198,7 @@
             on behalf of
           </span>
           <gr-account-label account="[[author]]" class="authorLabel"></gr-account-label>
-          <template is="dom-repeat" items="[[_getScores(message)]]" as="score">
+          <template is="dom-repeat" items="[[_getScores(message, labelExtremes)]]" as="score">
             <span class$="score [[_computeScoreClass(score, labelExtremes)]]">
               [[score.label]] [[score.value]]
             </span>
@@ -215,7 +218,7 @@
                 class="message hideOnCollapsed"
                 content="[[_messageContentExpanded]]"
                 config="[[_projectConfig.commentlinks]]"></gr-formatted-text>
-            <template is="dom-if" if="[[!_isMessageContentEmpty(message.message)]]">
+            <template is="dom-if" if="[[!_isMessageContentEmpty()]]">
               <div class="replyContainer" hidden$="[[!showReplyButton]]" hidden>
                 <gr-button link small on-click="_handleReplyTap">Reply</gr-button>
               </div>
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.js b/polygerrit-ui/app/elements/change/gr-message/gr-message.js
index 95109bb..d5505a4 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.js
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.js
@@ -17,8 +17,8 @@
 (function() {
   'use strict';
 
-  const PATCH_SET_PREFIX_PATTERN = /^Patch Set \d+: /;
-  const LABEL_TITLE_SCORE_PATTERN = /^([A-Za-z0-9-]+)([+-]\d+)$/;
+  const PATCH_SET_PREFIX_PATTERN = /^Patch Set \d+:\s*(.*)/;
+  const LABEL_TITLE_SCORE_PATTERN = /^(-?)([A-Za-z0-9-]+?)([+-]\d+)?$/;
 
   /**
    * @appliesMixin Gerrit.FireMixin
@@ -99,11 +99,13 @@
         },
         _messageContentExpanded: {
           type: String,
-          computed: '_computeMessageContentExpanded(message.message)',
+          computed:
+              '_computeMessageContentExpanded(message.message, message.tag)',
         },
         _messageContentCollapsed: {
           type: String,
-          computed: '_computeMessageContentCollapsed(message.message)',
+          computed:
+              '_computeMessageContentCollapsed(message.message, message.tag)',
         },
         _commentCountText: {
           type: Number,
@@ -166,29 +168,54 @@
       }
     }
 
-    _computeMessageContentExpanded(content) {
-      return this._computeMessageContent(content, true);
+    _computeMessageContentExpanded(content, tag) {
+      return this._computeMessageContent(content, tag, true);
     }
 
-    _computeMessageContentCollapsed(content) {
-      return this._computeMessageContent(content, false);
+    _computeMessageContentCollapsed(content, tag) {
+      return this._computeMessageContent(content, tag, false);
     }
 
-    _computeMessageContent(content, isExpanded) {
-      if (!content) return '';
+    _computeMessageContent(content, tag, isExpanded) {
+      content = content || '';
+      tag = tag || '';
+      const isNewPatchSet = tag.endsWith(':newPatchSet') ||
+          tag.endsWith(':newWipPatchSet');
       const lines = content.split('\n');
       const filteredLines = lines.filter(line => {
-        if (!isExpanded && line.startsWith('>')) return false;
-        if (line.startsWith('Patch Set ')) return false;
-        if (line.startsWith('(') && line.endsWith(' comment)')) return false;
-        if (line.startsWith('(') && line.endsWith(' comments)')) return false;
+        if (!isExpanded && line.startsWith('>')) {
+          return false;
+        }
+        if (line.startsWith('(') && line.endsWith(' comment)')) {
+          return false;
+        }
+        if (line.startsWith('(') && line.endsWith(' comments)')) {
+          return false;
+        }
+        if (!isNewPatchSet && line.match(PATCH_SET_PREFIX_PATTERN)) {
+          return false;
+        }
         return true;
       });
-      return filteredLines.join('\n').trim();
+      const mappedLines = filteredLines.map(line => {
+        // The change message formatting is not very consistent, so
+        // unfortunately we have to do a bit of tweaking here:
+        //   Labels should be stripped from lines like this:
+        //     Patch Set 29: Verified+1
+        //   Rebase messages (which have a ':newPatchSet' tag) should be kept on
+        //   lines like this:
+        //     Patch Set 27: Patch Set 26 was rebased
+        if (isNewPatchSet) {
+          line = line.replace(PATCH_SET_PREFIX_PATTERN, '$1');
+        }
+        return line;
+      });
+      return mappedLines.join('\n').trim();
     }
 
-    _isMessageContentEmpty(content) {
-      return this._computeMessageContent(content).trim().length === 0;
+    _isMessageContentEmpty() {
+      return !this._messageContentExpanded
+          || this._messageContentExpanded.length === 0;
     }
 
     _computeAuthor(message) {
@@ -247,17 +274,28 @@
       return event.type === 'REVIEWER_UPDATE';
     }
 
-    _getScores(message) {
-      if (!message.message) { return []; }
+    _getScores(message, labelExtremes) {
+      if (!message || !message.message || !labelExtremes) {
+        return [];
+      }
       const line = message.message.split('\n', 1)[0];
       const patchSetPrefix = PATCH_SET_PREFIX_PATTERN;
-      if (!line.match(patchSetPrefix)) { return []; }
+      if (!line.match(patchSetPrefix)) {
+        return [];
+      }
       const scoresRaw = line.split(patchSetPrefix)[1];
-      if (!scoresRaw) { return []; }
+      if (!scoresRaw) {
+        return [];
+      }
       return scoresRaw.split(' ')
           .map(s => s.match(LABEL_TITLE_SCORE_PATTERN))
-          .filter(ms => ms && ms.length === 3)
-          .map(ms => { return {label: ms[1], value: ms[2]}; });
+          .filter(ms =>
+            ms && ms.length === 4 && labelExtremes.hasOwnProperty(ms[2]))
+          .map(ms => {
+            const label = ms[2];
+            const value = ms[1] === '-' ? 'removed' : ms[3];
+            return {label, value};
+          });
     }
 
     _computeScoreClass(score, labelExtremes) {
@@ -265,6 +303,9 @@
       if ([score, labelExtremes].some(arg => arg === undefined)) {
         return '';
       }
+      if (score.value === 'removed') {
+        return 'removed';
+      }
       const classes = [];
       if (score.value > 0) {
         classes.push('positive');
diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
index 01bc691..20d87d2 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message_test.html
@@ -184,16 +184,72 @@
       assert.deepEqual(stub.lastCall.args[0].detail, {id: element.message.id});
     });
 
+    suite('compute messages', () => {
+      test('empty', () => {
+        assert.equal(element._computeMessageContent('', '', true), '');
+        assert.equal(element._computeMessageContent('', '', false), '');
+      });
+
+      test('new patchset', () => {
+        const original = 'Uploaded patch set 1.';
+        const tag = 'autogenerated:gerrit:newPatchSet';
+        let actual = element._computeMessageContent(original, tag, true);
+        assert.equal(actual, original);
+        actual = element._computeMessageContent(original, tag, false);
+        assert.equal(actual, original);
+      });
+
+      test('new patchset rebased', () => {
+        const original = 'Patch Set 27: Patch Set 26 was rebased';
+        const tag = 'autogenerated:gerrit:newPatchSet';
+        const expected = 'Patch Set 26 was rebased';
+        let actual = element._computeMessageContent(original, tag, true);
+        assert.equal(actual, expected);
+        actual = element._computeMessageContent(original, tag, false);
+        assert.equal(actual, expected);
+      });
+
+      test('ready for review', () => {
+        const original = 'Patch Set 1:\n\nThis change is ready for review.';
+        const tag = undefined;
+        const expected = 'This change is ready for review.';
+        let actual = element._computeMessageContent(original, tag, true);
+        assert.equal(actual, expected);
+        actual = element._computeMessageContent(original, tag, false);
+        assert.equal(actual, expected);
+      });
+
+      test('vote', () => {
+        const original = 'Patch Set 1: Code-Style+1';
+        const tag = undefined;
+        const expected = '';
+        let actual = element._computeMessageContent(original, tag, true);
+        assert.equal(actual, expected);
+        actual = element._computeMessageContent(original, tag, false);
+        assert.equal(actual, expected);
+      });
+
+      test('comments', () => {
+        const original = 'Patch Set 1:\n\n(3 comments)';
+        const tag = undefined;
+        const expected = '';
+        let actual = element._computeMessageContent(original, tag, true);
+        assert.equal(actual, expected);
+        actual = element._computeMessageContent(original, tag, false);
+        assert.equal(actual, expected);
+      });
+    });
+
     test('votes', () => {
       element.message = {
         author: {},
         expanded: false,
-        message: 'Patch Set 1: Verified+1 Code-Review-2 Trybot-Ready+1',
+        message: 'Patch Set 1: Verified+1 Code-Review-2 Trybot-Label3+1 Blub+1',
       };
       element.labelExtremes = {
         'Verified': {max: 1, min: -1},
         'Code-Review': {max: 2, min: -2},
-        'Trybot-Ready': {max: 3, min: 0},
+        'Trybot-Label3': {max: 3, min: 0},
       };
       flushAsynchronousOperations();
       const scoreChips = Polymer.dom(element.root).querySelectorAll('.score');
@@ -209,6 +265,25 @@
       assert.isFalse(scoreChips[2].classList.contains('min'));
     });
 
+    test('removed votes', () => {
+      element.message = {
+        author: {},
+        expanded: false,
+        message: 'Patch Set 1: Verified+1 -Code-Review -Commit-Queue',
+      };
+      element.labelExtremes = {
+        'Verified': {max: 1, min: -1},
+        'Code-Review': {max: 2, min: -2},
+        'Commit-Queue': {max: 3, min: 0},
+      };
+      flushAsynchronousOperations();
+      const scoreChips = Polymer.dom(element.root).querySelectorAll('.score');
+      assert.equal(scoreChips.length, 3);
+
+      assert.isTrue(scoreChips[1].classList.contains('removed'));
+      assert.isTrue(scoreChips[2].classList.contains('removed'));
+    });
+
     test('false negative vote', () => {
       element.message = {
         author: {},
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
index d54669f..05a6209f 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.html
@@ -64,6 +64,10 @@
         padding: var(--spacing-m) var(--spacing-xl);
         width: 100%;
       }
+      section.labelsContainer {
+        /* We want the :hover highlight to extend to the border of the dialog. */
+        padding: var(--spacing-m) 0;
+      }
       .actions {
         background-color: var(--dialog-background-color);
         bottom: 0;
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.html b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.html
index 1569094..06edb9b 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.html
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.html
@@ -67,10 +67,10 @@
             </div>
             <div class="diffContainer">
               <gr-diff
-              prefs="[[overridePartialPrefs(prefs)]]"
-              change-num="[[changeNum]]"
-              path="[[item.filepath]]"
-              diff="[[item.preview]]"></gr-diff>
+                prefs="[[overridePartialPrefs(prefs)]]"
+                change-num="[[changeNum]]"
+                path="[[item.filepath]]"
+                diff="[[item.preview]]"></gr-diff>
             </div>
           </template>
         </div>
diff --git a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.js b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.js
index 7561f1b..45e8c07 100644
--- a/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.js
+++ b/polygerrit-ui/app/elements/diff/gr-apply-fix-dialog/gr-apply-fix-dialog.js
@@ -75,6 +75,18 @@
           });
     },
 
+    attached() {
+      this.refitOverlay = () => {
+        // re-center the dialog as content changed
+        this.$.applyFixOverlay.fire('iron-resize');
+      };
+      this.addEventListener('diff-context-expanded', this.refitOverlay);
+    },
+
+    detached() {
+      this.removeEventListener('diff-context-expanded', this.refitOverlay);
+    },
+
     _showSelectedFixSuggestion(fixSuggestion) {
       this._currentFix = fixSuggestion;
       return this._fetchFixPreview(fixSuggestion.fix_id);
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
index 40fbe3c..021d962 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.html
@@ -18,6 +18,7 @@
 <link rel="import" href="../../../behaviors/fire-behavior/fire-behavior.html">
 <link rel="import" href="../gr-coverage-layer/gr-coverage-layer.html">
 <link rel="import" href="../gr-diff-processor/gr-diff-processor.html">
+<link rel="import" href="../../../elements/shared/gr-hovercard/gr-hovercard.html">
 <link rel="import" href="../gr-ranged-comment-layer/gr-ranged-comment-layer.html">
 
 <dom-module id="gr-diff-builder">
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
index 33cd4cb..05bff9f 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder.js
@@ -574,14 +574,30 @@
     const date = (new Date(commit.time * 1000)).toLocaleDateString();
     const blameNode = this._createElement('span',
         isStartOfRange ? 'startOfRange' : '');
-    const shaNode = this._createElement('span', 'sha');
-    shaNode.innerText = commit.id.substr(0, 7);
-    shaNode.onclick = function() {
-      location.href = '/q/' + shaNode.innerText;
-    };
 
+    const shaNode = this._createElement('span', 'blameDate');
+    shaNode.innerText = `${date}`;
+    shaNode.onclick = function() {
+      location.href = '/q/' + commit.id;
+    };
     blameNode.appendChild(shaNode);
-    blameNode.append(` on ${date} by ${commit.author}`);
+
+    const shortName = commit.author.split(' ')[0];
+    const authorNode = this._createElement('span', 'blameAuthor');
+    authorNode.innerText = ` ${shortName}`;
+    blameNode.appendChild(authorNode);
+
+    const hoverCardFragment = this._createElement('span', 'blameHoverCard');
+    hoverCardFragment.innerText =
+      `Commit ${commit.id}
+Author: ${commit.author}
+Date: ${date}
+
+${commit.commit_msg}`;
+    const hovercard = this._createElement('gr-hovercard');
+    hovercard.appendChild(hoverCardFragment);
+    blameNode.appendChild(hovercard);
+
     return blameNode;
   };
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
index 867a067..589d7c2 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-builder/gr-diff-builder_test.html
@@ -1146,6 +1146,30 @@
         assert.equal(result.getAttribute('data-line-number'), '3');
         assert.equal(result.firstChild, mocbBlameCell);
       });
+
+      test('_getBlameForBaseLine', () => {
+        const mockCommit = {
+          time: 1576105200,
+          id: 1234567890,
+          author: 'Clark Kent',
+          commit_msg: 'Testing Commit',
+          ranges: [1],
+        };
+        const blameNode = builder._getBlameForBaseLine(1, mockCommit);
+
+        const authors = blameNode.getElementsByClassName('blameAuthor');
+        assert.equal(authors.length, 1);
+        assert.equal(authors[0].innerText, ' Clark');
+
+        const date = (new Date(mockCommit.time * 1000)).toLocaleDateString();
+        Polymer.dom.flush();
+        const cards = blameNode.getElementsByClassName('blameHoverCard');
+        assert.equal(cards.length, 1);
+        assert.equal(cards[0].innerHTML,
+            `Commit 1234567890<br>Author: Clark Kent<br>Date: ${date}`
+          + '<br><br>Testing Commit'
+        );
+      });
     });
   });
 </script>
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
index ff52ddd..172a151 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.html
@@ -82,6 +82,7 @@
       }
       .diff-row {
         outline: none;
+        user-select: none;
       }
       .diff-row.target-row.target-side-left .lineNum.left,
       .diff-row.target-row.target-side-right .lineNum.right,
diff --git a/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.html b/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.html
index 77418df..475f6e2 100644
--- a/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.html
+++ b/polygerrit-ui/app/elements/shared/gr-dialog/gr-dialog.html
@@ -27,6 +27,7 @@
         color: var(--primary-text-color);
         display: block;
         max-height: 90vh;
+        overflow: auto;
       }
       .container {
         display: flex;
@@ -42,6 +43,13 @@
         display: flex;
         flex-shrink: 1;
         width: 100%;
+        flex: 1;
+        /* IMPORTANT: required for firefox */
+        min-height: 0px;
+      }
+      main .overflow-container {
+        flex: 1;
+        overflow: auto;
       }
       footer {
         display: flex;
@@ -58,7 +66,11 @@
     </style>
     <div class="container" on-keydown="_handleKeydown">
       <header class="font-h3"><slot name="header"></slot></header>
-      <main><slot name="main"></slot></main>
+      <main>
+        <div class="overflow-container">
+          <slot name="main"></slot>
+        </div>
+      </main>
       <footer>
         <slot name="footer"></slot>
         <gr-button id="cancel" class$="[[_computeCancelClass(cancelLabel)]]" link on-click="_handleCancelTap">