This is something odd, when a contentpane is undocked and moved into a floating state PRISM V4 RegionManager seems to loose a reference to that ContentPane's injected region, causing some of my code that depends on this to fail.
Note: Re-docking seems to add the region back into the RegionManagers collection.
Any suggestions? I can probably figure this one out or a way around it but i wanted to bring it to your attention and see if perhaps you already have a solution.
Floating panes are hosted in a separate WPF Window so you probably need to handle the ToolWindowLoaded event and use the RegionManager.SetRegionManager method to set the region manager on the e.ToolWindow.
This seems to have done the trick. One more question though, what is the best way to see if a floating window is being created vs. the standard "ToolWindowLoaded" events that are fired during initialization for my docked SplitePanes?