anchor.diff:    final List<core.AffineTransform> _transforms;
     final bool cacheEnabled;
     final core.EventHandle<core.EventArgs> _updatedEventHandle;
  +  CanvasElement _cacheCanvas;
   
     num _width, _height, _alpha;
     core.Size _lastDrawSize;
  
positive.code:   //
  
    void drawInternal(CanvasRenderingContext2D ctx){
      // until we ar rocking caching, just draw normal
      _drawNormal(ctx);
    }
  
    void _drawNormal(CanvasRenderingContext2D ctx){
  
negative.code: 
    PElement(this._width, this._height, [this.cacheEnabled = false]) :
      _transforms = new List<core.AffineTransform>(),
      _updatedEventHandle = new core.EventHandle<core.EventArgs>();
  
    num get width() => _width;
  
  