Hi Greg Peter Joyal,
I wasn't able to reproduce the problem from my initial tests, but one of the things that worries me is that you are using the GetParentRadWindow in an incorrect way. Method GetParentRadWindow recurses the visual tree for parent of type RadWindow, for example if you create a user control and set is as a content to RadWindow, you would need to use it in order to get a reference to the window itself. Would you try to remove this method, and instead initiate new instance of RadWindow in which you programatically set the GridView control as content to the window. Please feel free to contact us any soon.
the Telerik team