Tab Mix Plus

I saw that there is an option to restore tabs on startup. I'm just wondering if it's implemented in a way such as vim, where it is constantly saving info to disk so that a catastrohpic power failure won't cause any loss of information, or if you need to do a clean exit if you are hoping to have your most recent tabs restored upon next startup of Firefox.

Secondary question: If you have 2 firefox windows, say each with 4 tabs, can it restore both of those, or is it only one of them (and which one)? This question applies to either the power failure case or the clean-close case (for a clean-close, obviously one of the FF windows would have been closed first, and the other last).

Thanks very much,

David

in the current builds, these features arent available however in future builds you would be able to