I have been using Matrox TH2G for a long time now, both in the analog and now in digital version.

I have always had a 4th screen coming off the second outlet of the video card.

Until recently I have never had any problem with this arrangement in FSX.  The fourth screen (setup as No2 and independent) always went black when FSX started in Full Screen, and I was able to park my choice of pop-up 2D panels and instruments as well as ATC there.

Also when the view was switched from VC to Spot, Tail etc the pop-ups did not disappear, which is a great advantage.

Now the fourth panel does not go black and become part of the presentation.  Occasionally it flashes black then reverts to the normal desktop.  However it is frozen as if it was 'in' the game, but won't allow pop-ups to be moved over to its surface.

I believe I have all the latest drivers and I have tried every resolution for the fourth screen without success.

Has anyone had this problem, and can they help me solve it, please?