Z-Order of DocumentWindow

Hello,

is there any possibiity to force a DocumentWindow to stay in background if activated?

Example in class MyDockSite: DockSite

protected override void OnActiveWindowChanged(DockingWindow oldValue, DockingWindow newValue)
{
base.OnActiveWindowChanged(oldValue, newValue);

if ((newValue is MyBackgroundWindow))
{
oldValue.Activate();
}
}

This Example does not work as expected, the newValue-Window ist still the active window.
What I want to achieve: I need a focusable Window as MdiBackground. If my background window has no focusable content, it stays in the back but if i add some focusable content i have to "deactivate" the activate-feature. Any hints or possibly a better solution to add content to your workspace background?

Wolfgang Hanke