On an up to date rolling Cauldron(KDE4) and also using the Live KDE4 DVD of M3B3 (64-bit) in live mode on the same PC, the desktop display is corrupted when certain web pages are displayed in Firefox (e.g. http://www.telegraph.co.uk). It can also occur when switching back and forth to full screen view (F11) in Firefox. The corruption causes the main window of Firefox to go black but window decorations are still displayed. All other application windows that were already open are not affected but any application that is then opened shows the same symptoms as the Firefox window. If it's a simple message display with no window decorations, e.g. clicking on the Application Launcher Menu icon, a black rectangle is displayed.
The situation can be recovered by simply logging out (<Ctrl><Alt><BSpace><Bspace>), and then log back in again.
This problem does not occur on an Mga2 installation in the same PC.
I have monitored journalctl and .xsession-errors but there are no obvious messages of any problems at the time of the error.
My videocard is an Intel 82Q35 Express Integrated Graphics Controller, using the "Intel 810 and later" module.
I first noticed this on or just before 22feb13 when Firefox 17.0.3 was released and all subsequent updates have not cured the problem. However, the problem does not occur with the Live KDE4 DVD of M3B3 on a different desktop PC which has an NVIDIA card, so I think it might be something to do with the Intel integrated graphics. I have been running the rolling Cauldron since just after the release of Mga1 and I have never seen this problem before.
If anyone has any idea what is happening or can point me to any logs that might help, I would be very grateful.
Steve