anchor.diff:      return tx;
     }
   
  -  void update(){
  -    _updatedEventHandle.fireEvent(EventArgs.empty);
  -  }
  +  void update(){ }
   
     void drawCore(CanvasRenderingContext2D ctx){
       if(cacheEnabled) {
  
positive.code: abstract class PElement extends AttachableObject {
    final List<AffineTransform> _transforms = new List<AffineTransform>();
    final bool cacheEnabled;
    final EventHandle<EventArgs> _updatedEventHandle = new EventHandle<EventArgs>();
    final EventHandle<EventArgs> _invalidatedEventHandle = new EventHandle<EventArgs>();
    CanvasElement _cacheCanvas;
  
  
negative.code: 
    void disposeInternal(){
      super.disposeInternal();
      _invalidatedEventHandle.dispose();
    }
  
  