Nope. Not there yet...

Settings window is a mess, with all but the first check icons at the right margin of the previous line instead of before the tab title (text overflow because the text doesn't quite fit?).
Opening pinned tabs in the same window opens them all in full (not pinned).
Opening them in a new window moves the first one to the last position and opens it not pinned.

Needs work to be of any use to me.

Three starts for effort.

If I understand it correctly, the panels in MySessions that I save or are autosaved - they are saved in the form of bookmarks. That means that Firefox shows me that every panel I have open has been bookmarked and I dont know if I did that and saved the link into an appropriate folder or if that is just from the MySessions addon. Is it possible to do something about it? Something like hide the MySessions bookmarks from the Firefox? Thanks

I'm still hoping for a function that auto-saved my personal saved Session.

See my PPS at the bottom of this please!

On the right way, but miles to go yet.

First, the author deserves kudos for investing his/her time to create a replacement for that long term friend of all of us who come here to devour the passing away of the classical session manager.

Importing old sessions is the most important and prominent function these days immediately after the release of FF57.

The makers at Firefox / mozilla may have underestimated the part that independant addon-creators have played over the years for the users - and the appreciation that users spent for those little marvels that made the base structure so popular.

Now, MySessions seems to have some labours to fight with yet. It is much better that the new Session Manager that made my i7, equipped with 12 GB of RAM, stall when trying to reconstruct a 6 window / 960 tabs session. It seems to try that all in RAM , the first time I saw a RAM usage of 96% on that machine - with an endless usage of virtual memory, blocking any normal use of the machine.

Now, MySessions seems to do better. But it also seems to try and load every single content of any tab - that should be optionally deselectable! In my case, about 80 YouTube videos all started to play, with the previously set AutoPlay also disregarded (not sure if MySessions is responsible for that). Plus old tabs that triggered some downloads reappeared too (all contained in the sessions, but if they would not have been re-loaded, they would have rested in peace there... Bad habit on my side, ok, but...

Opening the reconstructed sessions in new windows makes sense, but be sure to know what was your previously opened set of windows...

I offer and volunteer to act as a beta tester for future versions, as a heavy-duty user who always finds something... :)

So the two vacant stars offer space for perfection. Your turn!

P.S.: After posting this, I read the previous exchange between you and other users here. I understand that the question of having all tabs open is a known issue and subject to more work and a possible solution.

Would it be possible to freeze them all to hibernization piece by piece immediately at the time of loading them? Maybe optionally selectable in an options switch array? Who ever booted a DEC PDP11 or an MITS Altair 8800 or an IMSAI 8080, for that matter, some 35 years ago, loves those switches... ;)

PPS: Sitting at the machine with the previously 6 windows / 980 tabs in the continuous session. I can't find the previous sessions. I looked in C:\Users\\AppData\Roaming\Mozilla\Firefox\Profiles\phzsk6df.default\sessionstore-backups, there are a few files but none is called something like sessionsomething.

Before I found MySessions, I tried the other suggested replacement and had to stop that after several hours (!!!!) of activities by using task manager.
Can it be that "the other one" deleted all old session files? I had set the queue to a pretty large number, and there had always been long lists of previously saved session sets.
I understand this is not a help forum - where to turn best with such questions? Thanks!

Since there is no way to reply to a reply here, I try this way: (2017-Nov20, 01 p.m., CET)

The addon you suggested - thanks for that - has not got the most benevolent comments and was updated last time 2 months ago. What benefit should that have? Specially for tabs, that are completely reloaded, like a first load, during the reconstruction of the old lists? Wouldn't they get into the hibernation state only on the second start of the session they are contained in?

Getting used to it coming from session manager. Was able to recover saved session which is great!

Would be nice if it would not load all the tabs as active (request to server) but to just show the tab until selected and then load them (it would save time and memory). Usually my research sessions are tabs heavy and it takes forever to load not to mention it loads tabs I don't really want/need to load at that particular time. Also if there are multiple tabs with media in autoplay they all start playing together.

What would also be great: Send tab(s) to session S: I mean select tabs from one session and move them to another. I have my sessions saved by research theme and when in one session I bump into an article about other research, I'd love to select one or many tabs and "send to>" " session2"

Don't really fancy loading one session into a new window. Sessions should be "multiple windows" and when one session is loaded the other one is closed (or let us define that behaviour). Maybe I can live with that but I see my firefox eating my 16GB in an instant when two or more of my sessions co-exist.

Good job. Will provide better score if this issues are fixed. Thank you

would love if addon would not load all saved tabs