While I've learned to ignore most .xsession-errors, this one caught my eye. In full: (firefox-bin:2130): Gdk-WARNING **: XID collision, trouble ahead. I'm not noticing any problems with firefox or my system. Does anyone have an idea what this may be? Google turns up nothing of value. Edit: A little bit more googling and it is a known bug. While some seem to experience crashes because of it many don't. Some are also complaining of it filling up their logs (I must have 30 entries in a row). Still don't know what it means.