Undocked windows

Hi Folks.

Does anybody know how to keep the GPS on top over an undocked 3D cockpit view. I undock my virtual cockpit to be able to wrap it round  my three screens. But when I try to pull up the GPS, or any other gauges etc, for that matter, they are underneath the cockpit view and cannot be seen. If I get to the GPS and undock that, then as soon as I click on the screen anywhere it disappears underneath the cockpit view again. Is there a trick one can do to hold the GPS on top all the time please.

Thanks

John