event which is fired when the groupedColumns collection has changed. This event is fired also when group/ungroup from groupby modal dialog but key, layout and grid are not set. Use args.owner in order to access the groupby widget object. Use args.owner.grid to access the grid widget option. Use args.groupedColumns to get a reference to the current groupedColumns. Use args.key to get a reference to the current column's key that's being grouped. Use args.layout to get a reference to the current layout object, if any. Use args.grid to get a reference to the current child grid element, in case it's an hierarchical grid.
Target Platforms: Windows 8.1, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
