I need to format the group header text of a gridtemplatecolumn. Currently, I change the formatstring in the GroupsChanging event. Do you plan to add the possibility of using the FormatString directly in the GroupByExpression?
I think that you can set the format string of the template column in the markup or programmatically. The following links provide more info:
http://www.telerik.com/help/aspnet-ajax/grdgroupbydeclarativedefinition.html