diff --git a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
index b3478b1..7fc5973 100644
--- a/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
+++ b/polygerrit-ui/app/elements/change/gr-reply-dialog/gr-reply-dialog.ts
@@ -889,6 +889,10 @@
 
   _handleAttentionModify() {
     this._attentionExpanded = true;
+  }
+
+  @observe('_attentionExpanded')
+  _onAttentionExpandedChange() {
     // If the attention-detail section is expanded without dispatching this
     // event, then the dialog may expand beyond the screen's bottom border.
     this.dispatchEvent(