I have about 760 tabs in my session. I worked for an hour and a half with this add-on to set up my groups, and when I reopened FireFox, it had erased all of my work. This add-on thrashed my tabs, then refused to show the management screen. I could see it blink on, then disappear. Sadly, this add-on doesn't work with large tab sets. Good thing I backed up. [edit] Yes, session restore is enabled. Always has been. How else could you amass that many tabs?
Do you have session restore enabled in your browser settings? If not, then everything is obvious. Addon works well with 2000+ tabs, everything depends on the power of the computer hardware.
