Undocking Problem

I am having a problem when undocking which I have never had before. I go to window mode, undock, then move the chosen display to the second monitor, then go back to full screen. In the past, the second monitor would turn black except for the display I moved there-GPS, radios, etc. All worked fine.Now for some reason, when I do the same procedure, going back to full screen after docking, my main instrument panel is all black with the mouse/hour glass flickering. The display I docked to the second monitor goes black. If I go to VC, the main instrument panel shows up but has no instruments.I don't know of anything I could have done to cause this, not that I couldn't have. Anybody have a clue as to what's happening here?Jim