When I shut down my computer sometimes my app tabs do not reopen in Firefox and I need to remake all of them which is pretty annoying. I don't know if this is a common bug it might be specific to my computer.
I run Vista x64 and it just seems to still have quite a bit of problems. Sometimes when I command it to shut down it does not simply showing shut down loading for hours so I need to manually turn it off. I think that might be messing up Firefox but I'm not sure.
I also found a related thread on Bugzilla about this problem but I don't think it's the same issue as it only happens when I shut down my computer.