Comment 10 for bug 583891

@John Gilmore: I'm not entirely convinced this bug is a duplicate of bug #550850. The latter seems to be specific to Compiz, as the title itself entails, and users reportedly refer to Compiz, including you, while the present bug report also includes Kubuntu, which relies on Kwin as a window manager.

As I understand from the original report and various comments, including yours, in bug #550850 it's just Compiz to exit, but X is not crashing as reported in this bug. You report that the "window manager goes away", leaving you with undecorated windows, and that you're still able to log out and then back in to temporarily solve the issue. Also, you add that when it happens, you "can usually type into a terminal and/or a web browser, so there's lots that could be done". Conversely, this bug reports X crashing and taking users straight to the login screen (imagine hitting Ctrl+Alt+Backspace in the old days, to get the effect), and when that happens there's not much we can actually do apart from logging back in.