Great addon! Unloads tabs to the same state as when Firefox is closed and reopened when it is configured to restore last session. Really appreciate that it has context menus on both the tab bar and on web sites and that both can be toggled on and off. Makes it usable when I hide the tab bar and use sidebars that work as replacements. Didn't really work correctly on Firefox 58 but it seems to work on Firefox Nightly 59 and I haven't noticed any issues with it yet!