I actually came here to make a similar post myself. I've been having some trouble using the WPF Studo docking system w/ Composite WPF (Prism).
The fist problem is that the standard SelectorRegionAdapter, when applied to a ToolWindowContainer, simply does not work properly. I forget the details, but it was pretty obvious at runtime. The problem stems from the fact that the standard SelectorRegionAdapter works by binding the ItemsSource property of the Selector to its view collection, and the ToolWindowContainer does not seem to handle this behavior. As a temporary workaround, I modified the SelectorRegionAdapter such that it directly operates on the Items collection property instead (source code is here
My new problem is that when I use this modified SelectorRegionAdapter on a TabbedMdiContainer, the document tabs show up in the MDI container, but not in the Active Files list in the Switcher. They do not show up in the drop-down document list either. However, if I open several document tabs and then close one of them, the remaining documents now show up in the Switcher and the drop-down document list. If I then open more documents, the new documents will not show up in the switcher until I close another one; the drop-down list, on the other hand, is updated in real time after the first document was closed. Strange.
I think Composite WPF presents a great usage scenario for the WPF Studio docking system, so it would be great if steps were taken to ensure that they play nice together "out of the box". To that end, I have one last suggestion: it would be nice if the ItemsControls in the docking system (i.e. ToolWindowContainer) would automatically generate containers (i.e. ToolWindows) for any regular objects added to the Items collection. You could add properties like "TitleMemberPath" to ToolWindowContainer to specify default bindings for the generated ToolWindow's properties like "Title".
Aside from my initial hiccups with the region adapter and my continued documents/switcher problem, I'm happy to say that the docking system has been working quite nicely in WPF Studio :). It's far more flexible than the other docking solutions I've used. Kudos.
[Modified at 08/26/2008 11:13 AM]