I've been looking for a Visual Studio-like docking library for WinForms, but the two most popular and complete options (WeifenLuo.WinFormsUI.Docking and the MagicLibrary) both use P/Invokes extensively, so I can't use them in Mono.
The best I can manage so far is toggling a Panel from being hosted by the main form or by a toolwindow that's made on the spot by setting the control's Parent. This is nowhere near the functionality I'm looking for, as I'm sure you can understand.