I used the example here to create a floating window; http://avalondock.codeplex.com/Thread/View.aspx?ThreadId=30280
DockingManager.Show() doesn't have an overload which takes a DocumentContent and a DockableContentState so you're forced to pass it a DockableContent.
When the floating window is docked back onto the dockable area, it turns into a DockableContent (as in you see the solid title bar or DockableContent not the tab of a DocumentContent).
Is there any way to create a floating document through code?
Also, I noticed that closing DocumentContent often leaves a gap, unlike closing DockableContent where the space left over is eaten up by the surrounding contents.