anchor.diff:        remove(resizeHandler);
     }
   
  -  _drawBackground([_]) {
  +  _drawBackground([event]) {
       print('_drawBackground');
       if (bg != null) return;
   
  
positive.code:     });
    }
  
    _drawElement([_]) {
      document.body.nodes.add(el);
  
      window.document.documentElement.rect.then((document) {
  
negative.code:       show();
    }
  
    void remove() => hide();
  
    void hide() {
      _removeHandlers();
      bg.remove();
      el.remove();
    }
  
    void show() {
  