anchor.diff:    static final Property<bool> _isClickableProperty =
         new Property<bool>("isClickable", false);
   
  +  static final Property<bool> _isDraggableProperty =
  +      new Property<bool>("isDraggable", false);
  +
     static final AttachedEvent<ThingMouseEventArgs> _clickEvent =
         new AttachedEvent<ThingMouseEventArgs>('clickEvent');
   
  
positive.code:     final args = new ThingMouseEventArgs(thing, e);
      _clickEvent.fireEvent(thing, args);
    }
  }
  
negative.code:     _stage._canvas.on.mouseOut.add(_mouseOut);
      _stage._canvas.on.mouseUp.add(_mouseUp);
      _stage._canvas.on.mouseDown.add(_mouseDown);
  
      window.on.mouseMove.add(_windowMouseMove);
      window.on.mouseUp.add(_windowMouseUp);
      window.on.blur.add(_windowBlur);
    }
  
    static void setCursor(Thing thing, String value) {
  