Aircraft Selection Screen Appears Blank

Every now and then, if I try to switch aircraft while in FSX, my aircraft selection screen will be blank. The dropdown menus still work, but no aircraft populate on the screen. It only happens when I try to switch aircraft. It never occurs on initial start-up of FSX.

I believe the problem began after I installed the Eaglesoft Citation X 2.0, but I can't be certain. The frustrating thing is that I have solved this problem before, but I can't remember for the life of me how I fixed it. I must be getting old.

Thanks for the help!