For some reason, every now and then, my the previews for windows don't show properly. They seem to show other windows as well and will overlap. I have included an attachment of what it looks like. I can't figure out what does it, but in this instance moving all the windows to the main monitor and then back fixed the issue. I have been seing this since 4.0.

4.0.1 Pro on Windows 7 64-bit Pro.

Not sure. I will try to take note of when it happens again. As of this moment, all is working properly.

I want to say Excel is one of the biggest culprits. Here is one example I can duplicate pretty reliably. If i open a excel document and then open another excel document (so their are now 2 excel documents full screen) and then minimize the excel window, I There are no thumbnails whatsoever. (see screenshot). Sometimes I have to minimize then maximize then minimize a second time, but generally it happens on the first try. Some of this may be due to the odd nature of how excel works. If you open multiple excel documents they are technically in the same "instance". ie. if i move excel to the other screen, all open spreadsheets move or if i miinimize one document, all excel documents move. I am not able to duplicate this of I have 2 truly independent excel screens. So if open a documents and then run excel again and then open a document in that excel. Then the 2 windows are independent on each other (I can put one on each screen).

I will post other similar screenshot and steps here as well.

Oddity #2. Whenever I have open 2 excel windows, it only shows me the "cells" part of the preview. It does not show menu the menu part with the SmartBar and menu options.

Sure enough. Hadn't even noticed. Thanks.