You'll get "pieces" of your desktop/other applications showing up in dosbox at the bottom (a few lines only), it's a bug from the drivers apparently:

http://www.driverheaven.net/showthread.php?t= … 51&page=3&pp=15

took me a while to find out what was wrong, but that's a post from the author saying there's a bug in those drivers, unless I misread.. And this is exactly the problem I've been having (and white flickering when I alt-tab out)

I use those drivers since they're the best for quality.. Gotta wait till they fix it up I guess