Allow RadWindow to float out of the main window in OOB. This will let the Docking control ToolWindows to also float out of the main window.
ScrollViewer, using ScrollViewerTouchScrollBehavior (from Wintellect Touch Library) into a RadWindow is not scrollable.
There is an easy workaround - show the window in the Loaded event handler. 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.