anchor.diff:    VGroup _gridContainer;
     HGroup _headerBounds, _headerContainer;
     ListRenderer _list;
  +  bool _isSelectedIndexUpdateRequired = false;
     
     ListRenderer get list => _list;
   
  
positive.code:       _isColumnsChanged = false;
  
        _updateColumnsAndHeaders();
      }
    }
    
  
negative.code:   void _dataProvider_collectionChangedHandler(List<ListChangeRecord> changes) {
      super._dataProvider_collectionChangedHandler(changes);
      
      _isSelectedIndexUpdateRequired = true;
    }
    
    @override
  