diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index 3a7d916ca..412527c93 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -720,6 +720,7 @@ var ThumbnailsBox = GObject.registerClass({
     }
 
     _onDestroy() {
+        this._destroyThumbnails();
         this._unqueueUpdateStates();
 
         if (this._scrollValueId)