anchor.diff:    }
   
     Size get size(){
  -    return new Size(width, height);
  +    return new Size(_width, _height);
     }
  +  
  +  num get width(){ return _width; }
  +  num get height(){ return _height; }
   
     AffineTransform getTransform() {
       var tx = new AffineTransform();
  
positive.code:   }
  
    void _invalidateParent(){
      if(_lastDrawSize != null){
          assert(this._parent != null);
        _parent.childInvalidated(this);
      }
    }
  }
  
negative.code:   }
  
    void invalidateDraw(){
      if(_lastDrawSize != null){
        _lastDrawSize = null;
        _invalidateParent();
      }
    }
  
    bool hasVisualChild(PElement element){
  