anchor.diff:    }
   
     Widget build() {
  -    // TODO(hansmuller) The code below changes the widget tree when
  -    // the user starts dragging. Currently this causes Sky to drop the
  -    // rest of the pointer gesture, see https://github.com/domokit/mojo/issues/312.
  -    // As a workaround, always create the Transform and Opacity nodes.
  -    Widget transformedChild = child;
  -    if (_isActive) {
  -      transformedChild = _transform.build(transformedChild);
  -    } else {
  -      transformedChild = new Transform(child: transformedChild, transform: new Matrix4.identity());
  -      transformedChild = new Opacity(child: transformedChild, opacity: 1.0);
  -    }
  -
  +    Matrix4 transform = new Matrix4.identity();
  +    transform.translate(_position.value.x, _position.value.y);
       return new Listener(
         onPointerDown: _handlePointerDown,
         onPointerMove: _handlePointerMove,
  
positive.code:       onPointerCancel: _handlePointerUpOrCancel,
        onGestureFlingStart: _handleFlingStart,
        child: new SizeObserver(
          child: transformedChild,
          callback: _handleSizeChanged
        )
      );
    }
  
negative.code: 
    void _handleSizeChanged(Size newSize) {
      _width = newSize.width;
      _position.end = _activeCardDragEndPoint;
    }
  
    void _handlePointerDown(sky.PointerEvent event) {
  