Related to my earlier question about making floating windows independent from the main DockingManager, here's a similar, but hopefully simpler one:
Can AvalonDock floating windows be made not to be "Always On Top" of the main DockingManager window?
I'm rummaging around in the AvalonDock source code trying to find a way to do this, but I haven't found anything that works yet.
Ideally, I'm after something which has the same effect as Visual Studio's Tools > Options > Environment > Tabs and Windows > Floating tool windows always stay on top of the main window
(available in at least VS2013 and VS2015).