diff --git a/js/game.js b/js/game.js
index 88a97e9..45e7754 100644
--- a/js/game.js
+++ b/js/game.js
@@ -982,7 +982,9 @@ export class Level {
     }
 
     undo() {
+        //ok, actually we're not doing an in-progress move after all.
         this.waiting_for_input = false;
+        this.pending_undo = [];
         this.aid = Math.max(1, this.aid);
 
         let entry = this.undo_stack.pop();