Clears the grouping applied to the View and returns the group columns to display in the View.
The method clears grouping and adds the group columns to the end of the ColumnView.Columns collection.
If you need to cancel grouping by a particular column, set the column’s GridColumn.GroupIndex property to -1. In this case, the column is hidden from the View. Use its GridColumn.VisibleIndex property to show it again.
Please refer to the Grouping topic for additional information on grouping data.