Besides closing the RadWindow control via its IsOpen property, it can be closed also when the user clicks on the Back button of the
phone or when the user taps outside of the window. Tha latter one won't be possible when using the RadWindow control in Fullscreen mode.
To toggle these two features of the RadWindow control you have to use the IsClosedOnBackButton and the
Here is an example.
<telerikPrimitives:RadWindow x:Name="radWindow" IsClosedOnBackButton="True" IsClosedOnOutsideTap="False" />