title: Return floating windows to previous dock position in AvalonDock
body: <p>As i understand, in Avalondock when you drag a LayoutDocument a Floating Windows is automatically created, but if you dont dock it in a new place then stays floating and thats what im trying to avoid. Is there a way to force the floating window to return to its previous state/dock position rather than stays floating?</p>
  
  <p>I'm using AvalonDock 2.0 in Visual Studio 2010.</p>