What about removing your Compiz configuration files? Maybe they have some old settings that cause conflicts with Qt4?

Hm, you are right ... I just tried to remove ~/.kde

Update: Tried this, too. But still the same problem.

I can confirm that the problem still exists in KDE 4.2 (at least in Kubuntu).
I can easily reproduce it on two different computers:
- resize application window
- close application to system tray
- click on system tray icon
- window shows up on the top left corner with small and annoying size

Tested with: Kontact, KDE Wallet Manager, KTorrent

I'm actually very surprised that not everyone can reproduce it.

2Dorgendubal: Try to disable "Legacy Fullscreen Support" stuff in the Worcaround section of CCSM.

waldelf wrote:kde-apps-forget-th ... 16536.html

i've got a similar problem.. and i am using kwin!
if only the apps would open maximized (as that is what i want most of the time)

no solution yet.. for now i configured every window separately (forced to maximize it)

Since the release of KDE 4.2 I'm using kwin and I think I have the same problem now.
But at least its not as annoying as with Compiz.

Sorry, guys. I copied a wrong nickname in my previous message. It was for you Rettich

Disabling of "Legacy Fullscreen Support" may be a solution for your problem with non-available wm borders in compiz/kde mix.

I don't use Compiz any longer and because the window decorator crashes every time I start Compiz (it's still installed) I can't test this anymore.

For me it crashes when i use the "KDE4 window decorator" for KDE 4.2, if it is "Emerald" decorator then everything is OK. Maybe it helps.

I didn't try Emerald. As I said, I switched to KWin and I'm quite happy now.
A great advantage is, that KWin stops all effects when I'm running my laptop on battery.

Edit: I tested Compiz with Emerald. Seems to work with and without "Legacy Fullscreen Support". Maybe this problem just appears with KDE4 window decorator. Or it is solved in KDE 4.2

It is not KWin that stops effects when you are on battery. It is PowerDevil.

But it only works with KWin

Yes because Powerdevil asks KWin to suspend compositing. It is not aware of other Window Managers.

And as fare as I know Compiz hasn't even a switch to turn off all effects.

Because Compiz is a compositing window manager. It cannot do anything without Compositing. KWin is a window manager with compositing effects.