anchor.diff:    //dom.MutationObserver _mObserver;
   
     bool _isDragActive = false;
  +  bool _isDragStartPending = false;
     math.Point<int> _dragStartPos;
     int _minLeft;
     int _maxLeft;
  
positive.code:           _dragEnd(e);
          }
        }
      });
    }
  
  
negative.code: 
    void _subscribeMouseMove() {
      _mouseMoveSubscr = dom.document.onMouseMove.listen((e) {
        if(_dragStartPos != null && _isDragStartPending) { // seems we still receive events after _mouseMoveSubscr.cancel()
          if(!_isDragActive) {
            if(((e.client.x - _dragStartPos.x) as int).abs() > distance && !_isDragActive) {
              _dragStart();
  