I'm running an up-to-date version of Ubuntu 12.04 which has been rock solid until two days ago when Firefox began crashing on a frequent, apparently random basis. By "crash," I mean that Firefox would close abruptly and the Mozilla dialog box sending a crash report to Mozilla would pop up. (I'll bet they love me, they must have 20 bug reports from me on this.)
The only non-standard (i.e., that don't come with Ubuntu) plug-ins I am running are NoScript and Firebug.
When I ran Firefox from terminal, I got the following error:
I disabled one plug-in at a time and restarted Firefox in normal mode. Removing NoScript and Firebug didn't prevent the crashes, but so far, disabling Global Menu Integration seems to have prevented the crashing.(firefox:5261): LIBDBUSMENU-GTK-CRITICAL **: dbusmenu_menuitem_property_set_shortcut: assertion `gtk_accelerator_valid(key, modifier)' failed
Once I thought I had Firefox behaving, Thunderbird crashed. I disabled the Global Menu Integration add-on in it, too, and so far, so good.
I do see a mention of an issue with Firefox and Unity's Global Menu Integration in the Firefox megathread which recommends either disabling them or uninstalling firefox-globalmenu. There don't seem to be a lot of details there, but apparently it's a known issue. It's just very weird it didn't strike me until now.
I can't think of anything I might have done that would have precipitated this kind of thing with Mozilla products. Does anyone have any more information about it?