anchor.diff:    return triggersOutsideAny((node) => node == element);
   }
   
  -/// Flag to enable new trigger logic which will use mouse down to determine if
  -/// a mouse up or click event should be listened to.
  -///
  -/// Defaults to true for DDC tests/development, and false for
  -/// dart2js tests/production when it is not explicitly set.
  -bool enableNewTriggerLogic;
  -
   /// A stream of click, mouseup or focus events of any node none of whose parents
   /// pass the check inside function.
   Stream<Event> triggersOutsideAny(Predicate<Node> checkNodeInside) {
  
positive.code:           controller.add(e);
          };
  
          // If new trigger logic is enabled listen to mouse down events. When it
          // is not enabled old logic will be used because the lastMouseDown event
          // will always be null.
          if (enableNewTriggerLogic) {
            // Keep track of mousedown events so that we can filter mouseup events
            // that occurred on a different element than the mousedown.
            mouseDownListener = document.onMouseDown.listen((MouseEvent e) {
              lastDownEvent = e;
            });
          }
  
          // Listen to mouseup to prevent scenarios where a single click event
          // both opens and closes an element.
  
negative.code:   StreamSubscription<MouseEvent> mouseDownListener;
    StreamSubscription<MouseEvent> mouseUpListener;
    EventListener listener;
  
    controller = StreamController.broadcast(
        sync: true,
  