diff --git a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
index 263fb28..da15406 100644
--- a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
+++ b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.html
@@ -42,12 +42,12 @@
         word-wrap: break-word;
       }
     </style>
-    <template is="dom-repeat" items="{{_files}}" as="file">
+    <template is="dom-repeat" items="[[_files]]" as="file">
       <div class="file">
         <a href$="[[_computeFileDiffURL(file, changeNum, patchNum)]]">[[file]]</a>:
       </div>
       <template is="dom-repeat"
-                items="[[_computeCommentsForFile(file)]]" as="comment">
+                items="[[_computeCommentsForFile(comments, file)]]" as="comment">
         <div class="container">
           <a class="lineNum"
              href$="[[_computeDiffLineURL(file, changeNum, comment.patch_set, comment)]]">
diff --git a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
index b40c18e..c23c373 100644
--- a/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
+++ b/polygerrit-ui/app/elements/change/gr-comment-list/gr-comment-list.js
@@ -19,17 +19,17 @@
 
     properties: {
       changeNum: Number,
-      comments: {
-        type: Object,
-        observer: '_commentsChanged',
-      },
+      comments: Object,
       patchNum: Number,
 
-      _files: Array,
+      _files: {
+        type: Array,
+        computed: '_computeFiles(comments)',
+      },
     },
 
-    _commentsChanged: function(value) {
-      this._files = Object.keys(value || {}).sort();
+    _computeFiles: function(comments) {
+      return Object.keys(comments || {}).sort();
     },
 
     _computeFileDiffURL: function(file, changeNum, patchNum) {
@@ -45,8 +45,8 @@
       return diffURL;
     },
 
-    _computeCommentsForFile: function(file) {
-      return this.comments[file];
+    _computeCommentsForFile: function(comments, file) {
+      return comments[file];
     },
 
     _computePatchDisplayName: function(comment) {
diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
index ae57be3..c89cb93 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.js
@@ -146,6 +146,10 @@
       };
       for (var label in this.permittedLabels) {
         var selectorEl = this.$$('iron-selector[data-label="' + label + '"]');
+
+        // The selector may not be present if it’s not at the latest patch set.
+        if (!selectorEl) { continue; }
+
         var selectedVal = selectorEl.selectedItem.getAttribute('data-value');
         selectedVal = parseInt(selectedVal, 10);
         obj.labels[label] = selectedVal;
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.html b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.html
index c6d8dbc..930c8cf 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.html
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.html
@@ -148,7 +148,7 @@
       <div class="rightItems">
         <gr-search-bar value="{{searchQuery}}" role="search"></gr-search-bar>
         <div class="accountContainer" id="accountContainer">
-          <a class="loginButton" href$="[[_computeRelativeURL('/login')]]" on-tap="_loginTapHandler">Sign in</a>
+          <a class="loginButton" href$="[[_loginURL]]" on-tap="_loginTapHandler">Sign in</a>
           <gr-account-dropdown account="[[_account]]"></gr-account-dropdown>
         </div>
       </div>
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js
index 186932a..6fc3cc1 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.js
@@ -56,6 +56,10 @@
         type: Array,
         computed: '_computeLinks(_defaultLinks, _userLinks)',
       },
+      _loginURL: {
+        type: String,
+        value: '/login',
+      },
       _userLinks: {
         type: Array,
         value: function() { return []; },
@@ -68,6 +72,18 @@
 
     attached: function() {
       this._loadAccount();
+      this.listen(window, 'location-change', '_handleLocationChange');
+    },
+
+    detached: function() {
+      this.unlisten(window, 'location-change', '_handleLocationChange');
+    },
+
+    _handleLocationChange: function(e) {
+      this._loginURL = '/login/' + encodeURIComponent(
+          window.location.pathname +
+          window.location.search +
+          window.location.hash);
     },
 
     _computeRelativeURL: function(path) {
diff --git a/polygerrit-ui/app/elements/core/gr-router/gr-router.js b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
index 9145ba1..dea0d1d 100644
--- a/polygerrit-ui/app/elements/core/gr-router/gr-router.js
+++ b/polygerrit-ui/app/elements/core/gr-router/gr-router.js
@@ -23,6 +23,12 @@
     // Middleware
     page(function(ctx, next) {
       document.body.scrollTop = 0;
+
+      // Fire asynchronously so that the URL is changed by the time the event
+      // is processed.
+      app.async(function() {
+        app.fire('location-change');
+      }, 1);
       next();
     });
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
index b827d26..a6e65ef 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-comment-thread/gr-diff-comment-thread.js
@@ -41,10 +41,6 @@
       _orderedComments: Array,
     },
 
-    get naturalHeight() {
-      return this.$.container.offsetHeight;
-    },
-
     observers: [
       '_commentsChanged(comments.splices)',
     ],
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
index 68fed9e..0e99a15 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.html
@@ -97,6 +97,7 @@
         color: #666;
       }
       .header {
+        align-items: center;
         display: flex;
         justify-content: space-between;
         margin: 0 var(--default-horizontal-margin) .75em;
diff --git a/polygerrit-ui/app/elements/gr-app.js b/polygerrit-ui/app/elements/gr-app.js
index 684120e..affcd44 100644
--- a/polygerrit-ui/app/elements/gr-app.js
+++ b/polygerrit-ui/app/elements/gr-app.js
@@ -17,6 +17,12 @@
   Polymer({
     is: 'gr-app',
 
+    /**
+     * Fired when the URL location changes.
+     *
+     * @event location-change
+     */
+
     properties: {
       params: Object,
       keyEventTarget: {