We recently added row group functionality to our grids and we and our users are very happy with this.

Only thing that bothers us is the drop functionality on the grouppanel. We have a wish to make the drop functionality of the grouppanel much more intuitive. Especially when the RadGrid is already grouped on multiple columns.

The marker to indicate where the user will drop an existing grouping column is shown at the begin and the end of the group column connector between groups:

The drop indicator on the group column connector should not be shown at the side of the connector where the dragged column is at to inform the user nothing will happen/change when you drop it here.

 All of these cases can be reproduced on the RadGrid Grouping demo on your site:
 http://demos.telerik.com/aspnet-ajax/grid/examples/functionality/grouping/grouping/defaultcs.aspx

Forum reference:
http://www.telerik.com/forums/grouppanel-column-drop-and-reorder?actionMode=replyPost&postId=d7274118-f8a1-48e1-9ae3-f537fe8d78de