I get that as well sometimes. If you have dual monitors try to move that bugged window to your second monitor then restart KFED. You can also try to change your resolution to something smaller start up KFED then change it back higher. Try those things in different combos and that's all I've ever found to work. Hope you get it : )
I think I've found an ACTUAL solution to the windows 7 problems.
I messed around with compatibility and the above suggestions but this didn't make a difference however I did find something that works all the time for me.
If you create a shortcut on your desktop > right click the icon > run as administrator.
This also works if you right click on the KFed.exe file.
I've tried clicking properties and setting it to run as admin in there but this doesn't work and you HAVE to "right click" then "run as administrator" for it to work properly, it's annoying to do it this way and so I'm looking for any commands that I can add to the shortcut to fix this.