It just happened to me, lxpanel crashed and is locked up. After reading this page it seems related.
I got this frowser open from terminal, it is still locked up (the panel) I closed 2 Libre Office windows that were open while Firefox was open and the panel crashed, locked yup is dead, no icons respond well the weqther one does and network one for some strange reason the rest are dead, even the cpu usage monitor stopped shows last , fixed view, etc. Nothing responds to mouse click, but the icons on my desktop do. Panel is llocked up. I can shutdown from the terminal of course, but I have a text file open that I really need to save last entry in, well. I can do that from terminal too reopen it, but I wanted to find the cause of this, Then I saw this bug report after i started searching the symptoms. Lubuntu 11.10 HP AMD Athlon, 32 bit box. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/927185 Title: Panel crashes if two OoO windows are closed via panel To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lxpanel/+bug/927185/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs