I've found that article regarding how to auto size the with of a column in a grid:
http://www.syncfusion.com/support/kb/grid/Default.aspx?ToDo=view&questId=70That works fine for my GridControls but not for my GridGroupingControls because there is no GridControlBase in GridGroupingControl.
What do I have to do to make this nice and helpfull peace of code (GridColSizeHelper.cs) to be working with GridGroupingControls?