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) {