Hi. Even though you might expect that as a main feature the addon description clearly states that you have to "Save them", at least that's the main reason of the addon. Now, I really don't know how to describe that better. Getting a 2 star rating for not having a feature that I never intended to add is quite odd.

Of course, there is a secondary aspect of the addon, the history tab will constantly save each 15 seconds (or how many you set) your current active session and you can find it there in case the browser crashes.

Of course things might not be exactly what you may expect, but that I can't change. The addon was designed to work with bookmarks and saving the session constantly into bookmarks would have been impossible. The addon main purpose is to be a session management tool, not an auto-saving session (although it does have that as well in the History tab)