anchor.diff:  
     get on => el.on;
     get parent => el.parent;
  -  ElementList queryAll(String selectors) => el.queryAll(selectors);
  +  List<Element> queryAll(String selectors) => el.queryAll(selectors);
     Element query(String selectors) => el.query(selectors);
   
     _attachHanders() {
  
positive.code:       remove(resizeHandler);
    }
  
    _drawBackground([_]) {
      print('_drawBackground');
      if (bg != null) return;
  
  
negative.code:       show();
    }
  
    void remove() => hide();
  
    void hide() {
      _removeHandlers();
      bg.remove();
      el.remove();
    }
  
    void show() {
  