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 e6d89a1..7e4cf2c 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
@@ -1284,6 +1284,10 @@
     if (value.basePatchNum === undefined)
       value.basePatchNum = ParentPatchSetNum;
 
+    if (value.patchNum === undefined) {
+      value.patchNum = computeLatestPatchNum(this._allPatchSets);
+    }
+
     const patchChanged = this.hasPatchRangeChanged(value);
     let patchNumChanged = this.hasPatchNumChanged(value);