Dual monitors: FS produces CTD undocking FMC. Why ?

My only glitch with the NG and my PC system is as follows:When I undock the FMC in the NG and drag it to a second monitor, what often (but not always!) happens is that the mouse pointer starts to flicker and alternate between a pointer arrow and the egg-timer processor. It does this the instant the image of the FMC appears on Monitor 2 while being dragged from the primary monitor.If I drag the FMC back to the primary monitor when this flickering commences, the flickering effect stops and all is normal on the primary monitor. But if I leave the FMC on the secondary monitor, the flickering goes on for about 1-2 mins and then I get a CTD.I use Windowed mode on the primary monitor. The second monitor displays FSNavigator and instruments. I am baffled as to why this happens. I've tried saving situations and reloading to see if it makes a diff, but the flickering effect seems to be random. Sometimes I can load a saved PMDG situation and have the FMC on the second monitor with FSNavigator -- like yesterday, for 5 hours--and all works fine.I am sure there is a specific cause for this flickering effect and CTD, but what it is is beyond me.Can anybody help, please?Thanks!Jonathan