Ok, this is a weird one. Due to the logout/session crash I can not give you a backtrace (At least I don't know how). Reproducible: Always Steps to Reproduce: 1. Start Konsole and use the left or right screen edge to resize it to 1/4 or 1/2 screen size (both work) 2. Then try to maximise it by using the top screen edge. 3. After about one second Konsole crashes (this is what I think) and I am back at the lightdm login screen. I have tried this with different programs (rekonq, kate) but only with konsote I am experiencing this bug. If you have some advises how to create a backtrace: I would be glad to help.
Sorry to say, but for such xorg server crash, the blame should go to the video driver. See http://forum.kde.org/viewtopic.php?f=227&t=109597&sid=bd97a0e05ce5dc09dcf38ffff59e6fbc