Arch Linux

When Qt requests a window to go fullscreen, and (!) the window is currently maximized, xfce-panel is drawn on top of the 'fullscreen' window in either of two scenarios:

1. As soon as a GUI element in Qt has its visibility changed (eg. menubar hidden)
2. If a GUI element is programatically hidden right before requestion fullscreen, the issue immediately manifests itself

Note for 2: interestingly, if a GUI element is hidden 'manually' (eg. by doing so as a key is pressed) and fullscreen is requested using another keypress, xfce-panel is NOT drawn on top of the fullscreen window.

A real-world occurance of this bug is VLC: requesting fullscreen with a maximized window results in xfce-panel showing on top of the video.

I've attached a testcase which can be used to reproduce the issue (requires python2-pyqt)

Versions at time of writing are: xfwm 4.8.3 Qt 4.8.0

Additional notes:
- I've been able to narrow occurence of this bug down to Qt/Xfce, but am not entirely sure which of the two is responsible. The fact that the issue doesn't seem to be reproducable on non-Xfce desktops suggests xfwm might be at fault.
- I was unable to reproduce this on a Xubuntu 11.10 livecd instance
- This is probably an upstream bug, but as it is unclear which component is to blame, I've reported it here