UPDATE 2019-09-12: There has been an added Trash button to the Side Bar. AND you can change more of the size. THANK YOU for listening to us. Also, screw the haters and complainers.

I love this add on. However, I am not a huge fan of the changes. Specifically the size, and the fact the list and the delete button are on the opposite sides. I wish you would put another delete button in the list. I usually delete my saves ever few hours. Also, I only JUST recently donated. If you could have a way for the system to recognize it, so it would stop asking. You've worked super hard on this, and I appreciate it. I'm not looking for extras, for donating. Just a way to turn off the message. Thank You.

The best session manager! Everything what's needed!

Regarding bugs and session db losses during FFox updates - this is FFox bug, not the addon's. The only cure is - make backups of sessions and addon settings (via export), also is good to switch to manual FFox update and backuping whole profile before update.

Works great! Would love the option to merge windows when restoring sessions =)

Till Now, I had no problems, but today, 13 July 2019, this extension seems to have some problems with syncronisation of SOME tabs. Indeed, some of my tabs cannot be loaded and I cannot see what was in these tabs since they are empty now. Please correct these bugs, maybe due to a Firefox update. Thanks in advance. Eric from France.
UPDATE, 15 July 2019 : PROBLEM SOLVED, THANKS !

Supernützliches Addon.
HINWEIS: Wenn das Addon nicht funktioniert, wenn es nicht speichert:
Geht in die EInstellungen des Addons (über ADDON) und löscht alle Sitzungen. Danach funktioniert es wieder.

NOTE: If Addon not works or not Save Sessions:
Go to Settings of Addon (over Firefox ADDON Menu) and delete old Session Manger Sessions. After this, Addon works normaly

Спасибо, отлично работает.
Также спасибо за поддержку Tree style tabs.