Comment 6 for bug 60147

This also happens in KDE 3.5.4 and 3.5.5 in Edgy as well. No matter what you do if you logout/shutdown with firefox running, it remembers it as a 'crashed session'

Furthermore, this also happens on Dapper if you are using the tabmix plus plugin, which I gather is similar to what the 2.x branch of firefox uses by default. I've had this happen in Dapper with 1.5.0.5 - 1.5.0.7. So it seems like it's something to do with the extension and whatever it is they use by default in Edgy now in firefox.