Sorry, but I can't follow you, can you explain better what your gui should work, I mean what you are trying to do.
Regarding DockablePane with no DockableContents inside i was referring to this error:
This xaml is not correct:
<ad:DockablePane x:Name="dockablePane" />
because you are creating a resizepanel with only one child (the DockablePane) and also you're creating a DockablePane that is empty (means with no children DockableContents).
The equivalent xaml is:
When you restore a layout from disk, (using for example the initial layout you just posted) avalondock recreate all the structures (ResizingPanels, DockablePanes/DockableContents) and associate it with the current actual contents (MyUserControl1,MyUserControl2).
In your case before restoring the layout, MyUserControl1 and MyUserControl2 must be present into the xaml as children of dockingmanager.
For example starting from this xaml:
<ad:DockablePane x:Name="dockablePane" >
you can call the dockingManager.RestoreLayout() with your initial xml layout. After that you should notice that all the dockablecontents are not visible (because so is specified into the xml layout). At that point you can show them calling the DockingManager.Show()
Hope this helps,