diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index d897210..3f0c751 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -2052,7 +2052,7 @@
 comments for each path are sorted by patch set number. Each comment has
 the `patch_set` and `author` fields set.
 
-If the `enable_context` request parameter is set to true, the comment entries
+If the `enable-context` request parameter is set to true, the comment entries
 will contain a list of link:#context-line[ContextLine] containing the lines of
 the source file where the comment was written.
 
@@ -6699,7 +6699,7 @@
 this comment applies.
 |`context_lines` |optional|
 A list of link:#context-line[ContextLine] containing the lines of the source
-file where the comment was written. Available only if the "enable_context"
+file where the comment was written. Available only if the "enable-context"
 parameter (see link:#list-change-comments[List Change Comments]) is set.
 
 |===========================
diff --git a/java/com/google/gerrit/server/restapi/change/CommentJson.java b/java/com/google/gerrit/server/restapi/change/CommentJson.java
index cc8ad47..02f39ab 100644
--- a/java/com/google/gerrit/server/restapi/change/CommentJson.java
+++ b/java/com/google/gerrit/server/restapi/change/CommentJson.java
@@ -123,7 +123,6 @@
           list = new ArrayList<>();
           out.put(o.path, list);
         }
-        o.path = null;
         list.add(o);
       }
 
@@ -133,10 +132,11 @@
         loader.fill();
       }
 
+      List<T> allComments = out.values().stream().flatMap(Collection::stream).collect(toList());
       if (fillCommentContext) {
-        List<T> allComments = out.values().stream().flatMap(Collection::stream).collect(toList());
         addCommentContext(allComments);
       }
+      allComments.forEach(c -> c.path = null); // we don't need path since it exists in the map keys
       return out;
     }
 
diff --git a/plugins/codemirror-editor b/plugins/codemirror-editor
index 7357ab4..740c35a 160000
--- a/plugins/codemirror-editor
+++ b/plugins/codemirror-editor
@@ -1 +1 @@
-Subproject commit 7357ab473599d16ae33cc982bbd65472f08c2dd6
+Subproject commit 740c35ae36f44748b3c91e60ee7dcb2fb6e99549
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 febf18a..fdf2811 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
@@ -38,11 +38,7 @@
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {getPluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader';
 import {appContext} from '../../../services/app-context';
-import {
-  fetchChangeUpdates,
-  patchNumEquals,
-  CURRENT,
-} from '../../../utils/patch-set-util';
+import {fetchChangeUpdates, CURRENT} from '../../../utils/patch-set-util';
 import {
   changeIsOpen,
   isOwner,
@@ -1153,7 +1149,7 @@
 
   _getRevision(change: ChangeViewChangeInfo, patchNum?: PatchSetNum) {
     for (const rev of Object.values(change.revisions)) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         return rev;
       }
     }
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 0279b7e..f7bca82 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
@@ -258,7 +258,7 @@
           rev2: revObj,
         },
       };
-      assert.deepEqual(element._getRevision(change, '2'), revObj);
+      assert.deepEqual(element._getRevision(change, 2), revObj);
     });
 
     test('_actionComparator sort order', () => {
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index 684891f..126d017 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -69,7 +69,6 @@
   fetchChangeUpdates,
   hasEditBasedOnCurrentPatchSet,
   hasEditPatchsetLoaded,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {changeStatuses, changeStatusString} from '../../../utils/change-util';
@@ -1656,7 +1655,7 @@
     if (!this._change) throw new Error('missing required change property');
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
       fireAlert(this, 'Base is already selected.');
       return;
     }
@@ -1670,7 +1669,7 @@
     if (!this._change) throw new Error('missing required change property');
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
       fireAlert(this, 'Left is already base.');
       return;
     }
@@ -1685,7 +1684,7 @@
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum === latestPatchNum) {
       fireAlert(this, 'Latest is already selected.');
       return;
     }
@@ -1704,7 +1703,7 @@
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (!this._patchRange)
       throw new Error('missing required _patchRange property');
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum === latestPatchNum) {
       fireAlert(this, 'Right is already latest.');
       return;
     }
@@ -1724,8 +1723,8 @@
       throw new Error('missing required _patchRange property');
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (
-      patchNumEquals(this._patchRange.patchNum, latestPatchNum) &&
-      patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)
+      this._patchRange.patchNum === latestPatchNum &&
+      this._patchRange.basePatchNum === ParentPatchSetNum
     ) {
       fireAlert(this, 'Already diffing base against latest.');
       return;
@@ -1967,7 +1966,7 @@
         if (
           !this._patchRange ||
           !this._patchRange.patchNum ||
-          patchNumEquals(this._patchRange.patchNum, currentRevision._number)
+          this._patchRange.patchNum === currentRevision._number
         ) {
           // CommitInfo.commit is optional, and may need patching.
           if (currentRevision.commit && !currentRevision.commit.commit) {
@@ -2567,7 +2566,7 @@
     }
 
     const patchRange = patchRangeRecord.base || {};
-    return patchNumEquals(patchRange.patchNum, EditPatchSetNum);
+    return patchRange.patchNum === EditPatchSetNum;
   }
 
   _handleFileActionTap(e: CustomEvent<{path: string; action: string}>) {
@@ -2651,10 +2650,7 @@
       throw new Error('missing required _patchRange property');
     let patchNum;
     if (
-      !patchNumEquals(
-        this._patchRange.patchNum,
-        computeLatestPatchNum(this._allPatchSets)
-      )
+      !(this._patchRange.patchNum === computeLatestPatchNum(this._allPatchSets))
     ) {
       patchNum = this._patchRange.patchNum;
     }
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
index 1195ea6..c4526bb 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog.ts
@@ -246,8 +246,10 @@
   _computeDisableCherryPick(
     cherryPickType: CherryPickType,
     duplicateProjectChanges: boolean,
-    statuses: Statuses
+    statuses: Statuses,
+    branch?: BranchName
   ) {
+    if (!branch) return true;
     const duplicateProject =
       cherryPickType === CherryPickType.TOPIC && duplicateProjectChanges;
     if (duplicateProject) return true;
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
index 16262c6..4de395c 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_html.ts
@@ -85,7 +85,7 @@
   <gr-dialog
     confirm-label="Cherry Pick"
     cancel-label="[[_computeCancelLabel(_statuses)]]"
-    disabled$="[[_computeDisableCherryPick(_cherryPickType, _duplicateProjectChanges, _statuses)]]"
+    disabled$="[[_computeDisableCherryPick(_cherryPickType, _duplicateProjectChanges, _statuses, branch)]]"
     on-confirm="_handleConfirmTap"
     on-cancel="_handleCancelTap"
   >
diff --git a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
index ae34b70..5564fcf 100644
--- a/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
+++ b/polygerrit-ui/app/elements/change/gr-confirm-cherrypick-dialog/gr-confirm-cherrypick-dialog_test.js
@@ -174,6 +174,9 @@
     test('submit button is blocked while cherry picks is running', done => {
       const confirmButton = element.shadowRoot.querySelector('gr-dialog').$
           .confirm;
+      assert.isTrue(confirmButton.hasAttribute('disabled'));
+      element.branch = 'b';
+      flush();
       assert.isFalse(confirmButton.hasAttribute('disabled'));
       element.updateStatus(changes[0], {status: 'RUNNING'});
       flush(() => {
diff --git a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
index 27d9756..5949513 100644
--- a/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-download-dialog/gr-download-dialog.ts
@@ -20,7 +20,6 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-download-dialog_html';
-import {patchNumEquals} from '../../../utils/patch-set-util';
 import {changeBaseURL} from '../../../utils/change-util';
 import {customElement, property, computed, observe} from '@polymer/decorators';
 import {ChangeInfo, ServerInfo, PatchSetNum} from '../../../types/common';
@@ -72,7 +71,7 @@
     }
 
     for (const rev of Object.values(this.change.revisions || {})) {
-      if (patchNumEquals(rev._number, this.patchNum)) {
+      if (rev._number === this.patchNum) {
         const fetch = rev.fetch;
         if (fetch) {
           return Object.keys(fetch).sort();
@@ -113,7 +112,7 @@
     if (!change || !selectedScheme) return [];
     for (const rev of Object.values(change.revisions || {})) {
       if (
-        patchNumEquals(rev._number, patchNum) &&
+        rev._number === patchNum &&
         rev &&
         rev.fetch &&
         hasOwnProperty(rev.fetch, selectedScheme)
@@ -171,7 +170,7 @@
 
     let shortRev = '';
     for (const rev in change.revisions) {
-      if (patchNumEquals(change.revisions[rev]._number, patchNum)) {
+      if (change.revisions[rev]._number === patchNum) {
         shortRev = rev.substr(0, 7);
         break;
       }
@@ -185,7 +184,7 @@
       return false;
     }
     for (const rev of Object.values(change.revisions || {})) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         const parentLength =
           rev.commit && rev.commit.parents ? rev.commit.parents.length : 0;
         return parentLength === 0 || parentLength > 1;
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
index 3c99648..146b3e2 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header.ts
@@ -35,7 +35,6 @@
 import {
   computeLatestPatchNum,
   getRevisionByPatchNum,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {property, computed, observe, customElement} from '@polymer/decorators';
@@ -321,8 +320,7 @@
   _handlePatchChange(e: CustomEvent) {
     const {basePatchNum, patchNum} = e.detail;
     if (
-      (patchNumEquals(basePatchNum, this.basePatchNum) &&
-        patchNumEquals(patchNum, this.patchNum)) ||
+      (basePatchNum === this.basePatchNum && patchNum === this.patchNum) ||
       !this.change
     ) {
       return;
@@ -354,7 +352,7 @@
 
   _computePatchInfoClass(patchNum?: PatchSetNum, allPatchSets?: PatchSet[]) {
     const latestNum = computeLatestPatchNum(allPatchSets);
-    if (patchNumEquals(patchNum, latestNum)) {
+    if (patchNum === latestNum) {
       return '';
     }
     return 'patchInfoOldPatchSet';
diff --git a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
index cee0262..b8670c0 100644
--- a/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
+++ b/polygerrit-ui/app/elements/change/gr-file-list-header/gr-file-list-header_test.js
@@ -249,11 +249,11 @@
 
   test('class is applied to file list on old patch set', () => {
     const allPatchSets = [{num: 4}, {num: 2}, {num: 1}];
-    assert.equal(element._computePatchInfoClass('1', allPatchSets),
+    assert.equal(element._computePatchInfoClass(1, allPatchSets),
         'patchInfoOldPatchSet');
-    assert.equal(element._computePatchInfoClass('2', allPatchSets),
+    assert.equal(element._computePatchInfoClass(2, allPatchSets),
         'patchInfoOldPatchSet');
-    assert.equal(element._computePatchInfoClass('4', allPatchSets), '');
+    assert.equal(element._computePatchInfoClass(4, allPatchSets), '');
   });
 
   suite('editMode behavior', () => {
diff --git a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
index fc6b5ba..e6c9f42 100644
--- a/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-related-changes-list/gr-related-changes-list.ts
@@ -25,7 +25,7 @@
 import {htmlTemplate} from './gr-related-changes-list_html';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {ChangeStatus} from '../../../constants/constants';
-import {patchNumEquals} from '../../../utils/patch-set-util';
+
 import {changeIsOpen} from '../../../utils/change-util';
 import {getPluginEndpoints} from '../../shared/gr-js-api-interface/gr-plugin-endpoints';
 import {customElement, observe, property} from '@polymer/decorators';
@@ -410,7 +410,7 @@
       return [];
     }
     for (const rev in change.revisions) {
-      if (patchNumEquals(change.revisions[rev]._number, patchNum)) {
+      if (change.revisions[rev]._number === patchNum) {
         changeRevision = rev;
       }
     }
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
index 07045cd..2f3d03c 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.ts
@@ -46,10 +46,7 @@
   WeblinkType,
 } from '../gr-navigation/gr-navigation';
 import {appContext} from '../../../services/app-context';
-import {
-  convertToPatchSetNum,
-  patchNumEquals,
-} from '../../../utils/patch-set-util';
+import {convertToPatchSetNum} from '../../../utils/patch-set-util';
 import {customElement, property} from '@polymer/decorators';
 import {assertNever} from '../../../utils/common-util';
 import {
@@ -693,10 +690,7 @@
 
     // Diffing a patch against itself is invalid, so if the base and revision
     // patches are equal clear the base.
-    if (
-      params.patchNum &&
-      patchNumEquals(params.basePatchNum, params.patchNum)
-    ) {
+    if (params.patchNum && params.basePatchNum === params.patchNum) {
       needsRedirect = true;
       params.basePatchNum = null;
     } else if (!hasPatchNum) {
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 9988116..166f27e 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
@@ -18,7 +18,7 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-comment-api_html';
-import {patchNumEquals, CURRENT} from '../../../utils/patch-set-util';
+import {CURRENT} from '../../../utils/patch-set-util';
 import {customElement, property} from '@polymer/decorators';
 import {
   CommentBasics,
@@ -235,9 +235,7 @@
       allComments = allComments.concat(drafts);
     }
     if (patchNum) {
-      allComments = allComments.filter(c =>
-        patchNumEquals(c.patch_set, patchNum)
-      );
+      allComments = allComments.filter(c => c.patch_set === patchNum);
     }
     return allComments.map(c => {
       return {...c};
@@ -284,7 +282,7 @@
   getAllDraftsForPath(path: string, patchNum?: PatchSetNum): Comment[] {
     let comments = this._drafts[path] || [];
     if (patchNum) {
-      comments = comments.filter(c => patchNumEquals(c.patch_set, patchNum));
+      comments = comments.filter(c => c.patch_set === patchNum);
     }
     return comments.map(c => {
       return {...c, __draft: true};
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 601ea80..9574c1d 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
@@ -716,10 +716,19 @@
       }
 
       if (lineNumberEl) {
-        for (const layer of this.layers) {
-          if (typeof layer.annotate === 'function') {
-            layer.annotate(contentText, lineNumberEl, line);
+        const ANNOTATE_MAX_LINE_LENGTH = 1000;
+        // For performance reason, we skip annotating long lines.
+        if (line.text.length < ANNOTATE_MAX_LINE_LENGTH) {
+          for (const layer of this.layers) {
+            if (typeof layer.annotate === 'function') {
+              layer.annotate(contentText, lineNumberEl, line);
+            }
           }
+        } else {
+          const msg =
+            `A line is longer than ${ANNOTATE_MAX_LINE_LENGTH}.` +
+            ' Line annotation was skipped.';
+          console.warn(msg);
         }
       } else {
         console.error('The lineNumberEl is null, skipping layer annotations.');
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 828c53d..84b227b 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
@@ -44,7 +44,6 @@
 import {
   computeAllPatchSets,
   computeLatestPatchNum,
-  patchNumEquals,
   PatchSet,
 } from '../../../utils/patch-set-util';
 import {
@@ -880,12 +879,10 @@
 
   _displayDiffAgainstLatestToast(latestPatchNum?: PatchSetNum) {
     if (!this._patchRange) return;
-    const leftPatchset = patchNumEquals(
-      this._patchRange.basePatchNum,
-      ParentPatchSetNum
-    )
-      ? 'Base'
-      : `Patchset ${this._patchRange.basePatchNum}`;
+    const leftPatchset =
+      this._patchRange.basePatchNum === ParentPatchSetNum
+        ? 'Base'
+        : `Patchset ${this._patchRange.basePatchNum}`;
     fireAlert(
       this,
       `${leftPatchset} vs
@@ -896,12 +893,12 @@
 
   _displayToasts() {
     if (!this._patchRange) return;
-    if (!patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum !== ParentPatchSetNum) {
       this._displayDiffBaseAgainstLeftToast();
       return;
     }
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (!patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum !== latestPatchNum) {
       this._displayDiffAgainstLatestToast(latestPatchNum);
       return;
     }
@@ -916,17 +913,17 @@
       if (!hasOwnProperty(this._change.revisions, commitSha)) continue;
       const revision = this._change.revisions[commitSha];
       const patchNum = revision._number;
-      if (patchNumEquals(patchNum, this._patchRange.patchNum)) {
+      if (patchNum === this._patchRange.patchNum) {
         commit = commitSha as CommitId;
         const commitObj = revision.commit;
         const parents = commitObj?.parents || [];
         if (
-          patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum) &&
+          this._patchRange.basePatchNum === ParentPatchSetNum &&
           parents.length
         ) {
           baseCommit = parents[parents.length - 1].commit;
         }
-      } else if (patchNumEquals(patchNum, this._patchRange.basePatchNum)) {
+      } else if (patchNum === this._patchRange.basePatchNum) {
         baseCommit = commitSha as CommitId;
       }
     }
@@ -1250,7 +1247,7 @@
     if (!patchRange) return {patchNum, basePatchNum};
     if (
       patchRange.basePatchNum !== ParentPatchSetNum ||
-      !patchNumEquals(patchRange.patchNum, latestPatchNum as PatchSetNum)
+      patchRange.patchNum !== latestPatchNum
     ) {
       patchNum = patchRange.patchNum;
       basePatchNum = patchRange.basePatchNum;
@@ -1352,8 +1349,8 @@
 
     const {basePatchNum, patchNum} = e.detail;
     if (
-      patchNumEquals(basePatchNum, this._patchRange.basePatchNum) &&
-      patchNumEquals(patchNum, this._patchRange.patchNum)
+      basePatchNum === this._patchRange.basePatchNum &&
+      patchNum === this._patchRange.patchNum
     ) {
       return;
     }
@@ -1582,7 +1579,7 @@
     patchRangeRecord: PolymerDeepPropertyChange<PatchRange, PatchRange>
   ) {
     const patchRange = patchRangeRecord.base || {};
-    return patchNumEquals(patchRange.patchNum, EditPatchSetNum);
+    return patchRange.patchNum === EditPatchSetNum;
   }
 
   _computeBlameToggleLabel(loaded?: boolean, loading?: boolean) {
@@ -1641,7 +1638,7 @@
     if (!this._path) return;
     if (!this._patchRange) return;
 
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
       fireAlert(this, 'Base is already selected.');
       return;
     }
@@ -1658,7 +1655,7 @@
     if (!this._path) return;
     if (!this._patchRange) return;
 
-    if (patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)) {
+    if (this._patchRange.basePatchNum === ParentPatchSetNum) {
       fireAlert(this, 'Left is already base.');
       return;
     }
@@ -1680,7 +1677,7 @@
     if (!this._patchRange) return;
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum === latestPatchNum) {
       fireAlert(this, 'Latest is already selected.');
       return;
     }
@@ -1700,7 +1697,7 @@
     if (!this._patchRange) return;
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
-    if (patchNumEquals(this._patchRange.patchNum, latestPatchNum)) {
+    if (this._patchRange.patchNum === latestPatchNum) {
       fireAlert(this, 'Right is already latest.');
       return;
     }
@@ -1720,8 +1717,8 @@
 
     const latestPatchNum = computeLatestPatchNum(this._allPatchSets);
     if (
-      patchNumEquals(this._patchRange.patchNum, latestPatchNum) &&
-      patchNumEquals(this._patchRange.basePatchNum, ParentPatchSetNum)
+      this._patchRange.patchNum === latestPatchNum &&
+      this._patchRange.basePatchNum === ParentPatchSetNum
     ) {
       fireAlert(this, 'Already diffing base against latest.');
       return;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
index 04714bb..39d645e 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
@@ -38,7 +38,7 @@
   rangesEqual,
 } from './gr-diff-utils';
 import {getHiddenScroll} from '../../../scripts/hiddenscroll';
-import {isMergeParent, patchNumEquals} from '../../../utils/patch-set-util';
+import {isMergeParent} from '../../../utils/patch-set-util';
 import {customElement, observe, property} from '@polymer/decorators';
 import {
   BlameInfo,
@@ -605,10 +605,10 @@
       ? this.patchRange.basePatchNum
       : this.patchRange.patchNum;
 
-    const isEdit = patchNumEquals(patchNum, EditPatchSetNum);
+    const isEdit = patchNum === EditPatchSetNum;
     const isEditBase =
-      patchNumEquals(patchNum, ParentPatchSetNum) &&
-      patchNumEquals(this.patchRange.patchNum, EditPatchSetNum);
+      patchNum === ParentPatchSetNum &&
+      this.patchRange.patchNum === EditPatchSetNum;
 
     if (isEdit) {
       fireAlert(this, 'You cannot comment on an edit.');
diff --git a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
index ec39da2..671bd41 100644
--- a/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
+++ b/polygerrit-ui/app/elements/diff/gr-patch-range-select/gr-patch-range-select.ts
@@ -30,7 +30,6 @@
   getParentIndex,
   getRevisionByPatchNum,
   isMergeParent,
-  patchNumEquals,
   sortRevisions,
   PatchSet,
 } from '../../../utils/patch-set-util';
@@ -346,7 +345,7 @@
     patchNum: PatchSetNum,
     sortedRevisions: RevisionInfo[]
   ): boolean {
-    if (patchNumEquals(basePatchNum, ParentPatchSetNum)) {
+    if (basePatchNum === ParentPatchSetNum) {
       return false;
     }
 
@@ -441,7 +440,7 @@
       });
       detail.patchNum = patchSetValue;
     } else {
-      if (patchNumEquals(detail.basePatchNum, patchSetValue)) return;
+      if (detail.basePatchNum === patchSetValue) return;
       this.reporting.reportInteraction('left-patchset-changed', {
         previous: detail.basePatchNum,
         current: e.detail.value,
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
index d9a3187..fbf7f47 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment_html.ts
@@ -264,10 +264,16 @@
           </gr-account-label>
         </template>
         <template is="dom-if" if="[[showPortedComment]]">
-          <a href="[[_getUrlForComment(comment)]]">
-            <span class="portedMessage">
-              Ported from patchset [[comment.patch_set]]
-            </span>
+          <a href="[[_getUrlForComment(comment)]]"
+            ><span class="portedMessage"
+              >Ported from patchset [[comment.patch_set]]</span
+            ></a
+          >
+          <a
+            href="https://bugs.chromium.org/p/gerrit/issues/entry?template=Porting+Comments"
+            target="_blank"
+          >
+            <iron-icon icon="gr-icons:bug" title="report a problem"></iron-icon>
           </a>
         </template>
         <gr-tooltip-content
diff --git a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
index f313174..c163924 100644
--- a/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-dropdown-list/gr-dropdown-list_html.ts
@@ -145,7 +145,6 @@
       slot="dropdown-content"
       attr-for-selected="data-value"
       selected="{{value}}"
-      on-tap="_handleDropdownTap"
     >
       <template
         is="dom-repeat"
diff --git a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
index ae6e155..00f9a40 100644
--- a/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
+++ b/polygerrit-ui/app/elements/shared/gr-js-api-interface/gr-js-api-interface-element.ts
@@ -18,7 +18,7 @@
 import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {getPluginLoader} from './gr-plugin-loader';
-import {patchNumEquals} from '../../../utils/patch-set-util';
+
 import {customElement} from '@polymer/decorators';
 import {
   ChangeInfo,
@@ -154,7 +154,7 @@
 
     let revision;
     for (const rev of Object.values(change.revisions || {})) {
-      if (patchNumEquals(rev._number, patchNum)) {
+      if (rev._number === patchNum) {
         revision = rev;
         break;
       }
diff --git a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
index 078e07f..9e77784 100644
--- a/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
+++ b/polygerrit-ui/app/elements/shared/gr-rest-api-interface/gr-rest-api-interface.ts
@@ -36,11 +36,7 @@
 import {parseDate} from '../../../utils/date-util';
 import {getBaseUrl} from '../../../utils/url-util';
 import {appContext} from '../../../services/app-context';
-import {
-  getParentIndex,
-  isMergeParent,
-  patchNumEquals,
-} from '../../../utils/patch-set-util';
+import {getParentIndex, isMergeParent} from '../../../utils/patch-set-util';
 import {
   ListChangesOption,
   listChangesOptionsToHex,
@@ -1354,7 +1350,7 @@
     let params = undefined;
     if (isMergeParent(patchRange.basePatchNum)) {
       params = {parent: getParentIndex(patchRange.basePatchNum)};
-    } else if (!patchNumEquals(patchRange.basePatchNum, ParentPatchSetNum)) {
+    } else if (patchRange.basePatchNum !== ParentPatchSetNum) {
       params = {base: patchRange.basePatchNum};
     }
     return this._getChangeURLAndFetch({
@@ -1401,7 +1397,7 @@
     changeNum: NumericChangeId,
     patchRange: PatchRange
   ): Promise<FileNameToFileInfoMap | undefined> {
-    if (patchNumEquals(patchRange.patchNum, EditPatchSetNum)) {
+    if (patchRange.patchNum === EditPatchSetNum) {
       return this.getChangeEditFiles(changeNum, patchRange).then(
         res => res && res.files
       );
@@ -1983,9 +1979,10 @@
       }
       return res;
     };
-    const promise = patchNumEquals(patchNum, EditPatchSetNum)
-      ? this._getFileInChangeEdit(changeNum, path)
-      : this._getFileInRevision(changeNum, path, patchNum, suppress404s);
+    const promise =
+      patchNum === EditPatchSetNum
+        ? this._getFileInChangeEdit(changeNum, path)
+        : this._getFileInRevision(changeNum, path, patchNum, suppress404s);
 
     return promise.then(res => {
       if (!res || !res.ok) {
@@ -2277,8 +2274,7 @@
     };
     if (isMergeParent(basePatchNum)) {
       params.parent = getParentIndex(basePatchNum);
-    } else if (!patchNumEquals(basePatchNum, ParentPatchSetNum)) {
-      // TODO (TS): fix as PatchSetNum in the condition above
+    } else if (basePatchNum !== ParentPatchSetNum) {
       params.base = basePatchNum;
     }
     const endpoint = `/files/${encodeURIComponent(path)}/diff`;
diff --git a/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts b/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
index fadbfa7..d4bbe16 100644
--- a/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
+++ b/polygerrit-ui/app/elements/shared/revision-info/revision-info.ts
@@ -15,7 +15,6 @@
  * limitations under the License.
  */
 
-import {patchNumEquals} from '../../../utils/patch-set-util';
 import {ChangeInfo, PatchSetNum} from '../../../types/common';
 import {ParsedChangeInfo} from '../gr-rest-api-interface/gr-reviewer-updates-parser';
 
@@ -71,8 +70,8 @@
 
   getParentId(patchNum: PatchSetNum, parentIndex: number) {
     if (!this.change.revisions) return;
-    const rev = Object.values(this.change.revisions).find(rev =>
-      patchNumEquals(rev._number, patchNum)
+    const rev = Object.values(this.change.revisions).find(
+      rev => rev._number === patchNum
     );
     if (!rev || !rev.commit) return;
     return rev.commit.parents[parentIndex].commit;
diff --git a/polygerrit-ui/app/utils/comment-util.ts b/polygerrit-ui/app/utils/comment-util.ts
index 1ca100e..f4c0692 100644
--- a/polygerrit-ui/app/utils/comment-util.ts
+++ b/polygerrit-ui/app/utils/comment-util.ts
@@ -29,7 +29,7 @@
 import {parseDate} from './date-util';
 import {LineNumber} from '../elements/diff/gr-diff/gr-diff-line';
 import {CommentIdToCommentThreadMap} from '../elements/diff/gr-comment-api/gr-comment-api';
-import {isMergeParent, getParentIndex, patchNumEquals} from './patch-set-util';
+import {isMergeParent, getParentIndex} from './patch-set-util';
 
 export interface DraftCommentProps {
   __draft?: boolean;
@@ -202,7 +202,7 @@
   if (
     range.basePatchNum === ParentPatchSetNum &&
     comment.side === CommentSide.PARENT &&
-    patchNumEquals(comment.patch_set, range.patchNum)
+    comment.patch_set === range.patchNum
   ) {
     return true;
   }
@@ -210,7 +210,7 @@
   return (
     range.basePatchNum !== ParentPatchSetNum &&
     comment.side !== CommentSide.PARENT &&
-    patchNumEquals(comment.patch_set, range.basePatchNum)
+    comment.patch_set === range.basePatchNum
   );
 }
 
@@ -223,8 +223,7 @@
   range: PatchRange
 ) {
   return (
-    comment.side !== CommentSide.PARENT &&
-    patchNumEquals(comment.patch_set, range.patchNum)
+    comment.side !== CommentSide.PARENT && comment.patch_set === range.patchNum
   );
 }
 
@@ -253,7 +252,7 @@
       patchNum: comment.patch_set,
       basePatchNum: ParentPatchSetNum,
     };
-  } else if (patchNumEquals(latestPatchNum, comment.patch_set)) {
+  } else if (latestPatchNum === comment.patch_set) {
     return {
       patchNum: latestPatchNum,
       basePatchNum: ParentPatchSetNum,
diff --git a/polygerrit-ui/app/utils/patch-set-util.ts b/polygerrit-ui/app/utils/patch-set-util.ts
index fda302b..bda4658 100644
--- a/polygerrit-ui/app/utils/patch-set-util.ts
+++ b/polygerrit-ui/app/utils/patch-set-util.ts
@@ -60,19 +60,6 @@
 }
 
 /**
- * As patchNum can be either a string (e.g. 'edit', 'PARENT') OR a number,
- * this function checks for patchNum equality.
- *
- */
-export function patchNumEquals(a?: PatchSetNum, b?: PatchSetNum) {
-  if (a === undefined) {
-    return a === b;
-  }
-  // TODO(TS): replace with a===b when the whole code is converted to ts
-  return `${a}` === `${b}`;
-}
-
-/**
  * Whether the given patch is a numbered parent of a merge (i.e. a negative
  * number).
  */
@@ -114,7 +101,7 @@
   patchNum: PatchSetNum
 ) {
   for (const rev of revisions) {
-    if (patchNumEquals(rev._number, patchNum)) {
+    if (rev._number === patchNum) {
       return rev;
     }
   }
diff --git a/polygerrit-ui/app/utils/patch-set-util_test.js b/polygerrit-ui/app/utils/patch-set-util_test.js
index 29cc370..12f5ed4 100644
--- a/polygerrit-ui/app/utils/patch-set-util_test.js
+++ b/polygerrit-ui/app/utils/patch-set-util_test.js
@@ -21,7 +21,7 @@
   fetchChangeUpdates, findEditParentPatchNum, findEditParentRevision,
   getParentIndex, getRevisionByPatchNum,
   isMergeParent,
-  patchNumEquals, sortRevisions,
+  sortRevisions,
 } from './patch-set-util.js';
 
 suite('gr-patch-set-util tests', () => {
@@ -31,9 +31,9 @@
       {_number: 1},
       {_number: 2},
     ];
-    assert.deepEqual(getRevisionByPatchNum(revisions, '1'), revisions[1]);
+    assert.deepEqual(getRevisionByPatchNum(revisions, 1), revisions[1]);
     assert.deepEqual(getRevisionByPatchNum(revisions, 2), revisions[2]);
-    assert.equal(getRevisionByPatchNum(revisions, '3'), undefined);
+    assert.equal(getRevisionByPatchNum(revisions, 3), undefined);
   });
 
   test('fetchChangeUpdates on latest', done => {
@@ -231,17 +231,6 @@
         .assertWip(6, true); // PS6 was uploaded with WIP option
   });
 
-  test('patchNumEquals', () => {
-    assert.isFalse(patchNumEquals('edit', 'PARENT'));
-    assert.isFalse(patchNumEquals('edit', NaN));
-    assert.isFalse(patchNumEquals(1, '2'));
-
-    assert.isTrue(patchNumEquals(1, '1'));
-    assert.isTrue(patchNumEquals(1, 1));
-    assert.isTrue(patchNumEquals('edit', 'edit'));
-    assert.isTrue(patchNumEquals('PARENT', 'PARENT'));
-  });
-
   test('isMergeParent', () => {
     assert.isFalse(isMergeParent(1));
     assert.isFalse(isMergeParent(4321));