anchor.diff:      ..height = _headerHeight
       ..autoSize = false
       ..className = 'data-grid-header-container';
  +    
  +    _headerBounds = new HGroup()
  +      ..percentWidth = 100.0
  +      ..height = _headerHeight
  +      ..addComponent(_headerContainer);
   
       _list = new ListRenderer(orientation: 'grid')
       ..cssClasses = _listCssClasses
  
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);
  