Hi,

First the specs:

• Archlinux fully up to date
• Qt 4.7 (dist release, not self compiled)
• KDE 4.5.2 (and trunk)

Tested on application: QtCreator but occurs on all Qt apps. You just don't notice it if they are not maximized or in fullscreen.

Steps to reproduce this:
1. First open QtCreator and maximize it then close it again (just so it will open maximized next time you start it. If you already have it maximized you can skip this)
2. Open QtCreator. For a short (but noticeable) the app is maximized and entirely grey
3. A few milliseconds later QtCreator is drawn in that grey area with the unmaximized size
4. Another few miliseconds later the seems to be redrawn in the maximized state.
5. Now the app is finally done and you can use it.

Odd thing is that i didn't notice this behavior on Qt 4.6 so something must have changed in 4.7 besides the cool new features.
It has been suggested on irc (#qt-labs) that the following commits might cause this issue:
http://qt.gitorious.org/qt/qt/commit/8a895dbc
http://qt.gitorious.org/qt/qt/commit/cb530c33

Hope that's detailed enough to be reproducible. If required i can make a video of it.
Note: if you don't see this then run the same application through vallgrind which slows everything down a LOT but also makes it visible a lot longer.

Kind regards,
Mark