Please provide a property that will allow a message to be displayed to users when RadGridView is empty. 
Some users perception is that the program is not working properly when there is no data in the grid view so displaying a user-friendly message can be a useful way of preventing inquires and complaints.

Currently, when a user selects multiple rows, but skips a few, and then copies, the data in the Clipboard will look as if the selected rows were in an uninterrupted sequence. Unselected columns, on the other hand, leave a "hole" in the clipboard data. This

A kind of a workaround for the user: resize any column/the entire window or collapse the row details.

I would like to be bale to modify at once several cells of a GridViewComboBoxColumn, when using the common ItemsSourceBinding for all rows (in my GridView, the selection ​is: SelectionMode="Multiple" SelectionUnit="FullRow").
So I would like for the selected rows to apply the same value as the edited cell.

The functionality is documented at http://docs.telerik.com/devtools/wpf/controls/radgridview/filtering/icolumn-filter-descriptors and for the time being the functionality can be achieved by implementing an attached behavior. 

The issue seems to be a bug with UI Row Virtualization since once I set it to False, it did not occur any more. You can also refer to the documentation on UI Virtualization: http://docs.telerik.com/devtools/wpf/controls/radgridview/features/ui-virtualization.html

When tabbing in grouped RadGridView placed in Grid with another visual element inside it, GroupRenderMode is set to Flat  and second group is not in ViewPort, selected row changed its state to Unfocused.