diff --git a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
index 65e42a1..0902fe6 100644
--- a/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
+++ b/polygerrit-ui/app/elements/change/gr-message/gr-message.ts
@@ -663,7 +663,8 @@
       return;
     }
     e.stopPropagation();
-    this.message = {...this.message, expanded: true};
+    this.message.expanded = true;
+    this.requestUpdate();
   }
 
   private handleAuthorClick(e: Event) {
@@ -671,7 +672,8 @@
       return;
     }
     e.stopPropagation();
-    this.message = {...this.message, expanded: false};
+    this.message.expanded = false;
+    this.requestUpdate();
   }
 
   // private but used in tests.
diff --git a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
index c03121d..f6b0ad4 100644
--- a/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
+++ b/polygerrit-ui/app/elements/change/gr-messages-list/gr-messages-list.ts
@@ -324,7 +324,8 @@
       return;
     }
 
-    el.message = {...el.message, expanded: true};
+    el.message.expanded = true;
+    el.requestUpdate();
     await el.updateComplete;
     let top = el.offsetTop;
     for (