anchor.diff:        
         if (_autoManageScrollBars) _list.horizontalScrollPolicy = (tw > _width) ? ScrollPolicy.AUTO : ScrollPolicy.NONE;
         else _list.horizontalScrollPolicy = _horizontalScrollPolicy;
  +      
  +      if (_headerBounds != null) {
  +        _headerBounds.width = w;
  +        _headerBounds.height = _headerHeight;
  +      }
   
         if (_headerContainer != null) {
           _headerContainer.width = w;
  
positive.code:   List<IHeaderItemRenderer> get headerItemRenderers => _headerItemRenderers;
  
    VGroup _gridContainer;
    HGroup _headerContainer;
    ListRenderer _list;
    
    ListRenderer get list => _list;
  
negative.code:         )
      );
  
      _gridContainer.addComponent(_headerBounds);
      _gridContainer.addComponent(_list);
  
      addComponent(_gridContainer);
  