clicking on link in Software Update slideup notifier does nothing

toolkit/mozapps/update/src/nsBackgroundUpdateService.js

@@ -572,6 +572,17 @@ nsUpdateObserver.prototype = {
     updates.checkForUpdates([], 0, Components.interfaces.nsIUpdateItem.TYPE_ANY, 
                             Components.interfaces.nsIUpdateService.SOURCE_EVENT_USER,
                             null);
+  },
+  
+  /////////////////////////////////////////////////////////////////////////////
+  // nsISupports
+  QueryInterface: function (aIID) 
+  {
+    if (!aIID.equals(Components.interfaces.nsIObserver) &&
+        !aIID.equals(Components.interfaces.nsIAlertListener) && 
+        !aIID.equals(Components.interfaces.nsISupports))
+      throw Components.results.NS_ERROR_NO_INTERFACE;
+    return this;
   }
 };