Place a RadComboBox in the GridViewColumn header and set SelectedIndex in the xaml. The SelectionChanged event is fired, but the command is not executed. As a workaround you can set the SelectedIndex in xaml instead of on the Loaded event,
Hi, The XAML team has recently reviewed this issue and will not be addressing it as at this time the team is focusing on the bugs impacting the highest number of developers. If you have encountered this issue and it is blocking for your work please contact us through the support ticketing system with details on your setup and a reference to this item. This is a timing issue that appears only when the SelectedIndex is set in XAML and the Command property is bound to a property in the ViewModel. The Command doesn't execute as at the moment SelectionChanged is fired (due to the set SelectedIndex), the Command is not initialized yet. As workaround the SelectedIndex can be bound to the ViewModel as well or set in the Loaded event of the control. Regards, Kalin