Stopped displaying currently open session tabs, and doesn't show Save button unless full screen. It also started opening its own tab and using that generic non-descriptive tab name as the save title for every save. Don't know why this has changed. Pretty well killed it for me.

How can you support nonstandard functionality like tree tabs but NOT pagination? One of the most basic elements of browser navigation for decades, even before tabs? Firefox by default is capable of storing and restoring page serializations of tabs. TSM can't carry that forward? There's something inscrutable about how open-source Firefox stores this data?

Hope I don't have to explain why, especially in the HTML5 era, a user might prefer to paginate over opening a new tab for every single webpage. Not to make a competition out of different wishlists for this extension, but it boggles my mind that there could even be asks or feedback overlooking this fundamental part of session maintenance. For me, it's the difference between the add-on being a lifesaver and mostly useless. I thought I found a great solution to a terrible problem, but not at all. Currently, not at all.

No export for sessions though it says you can export. The most telling is there is no importing of sessions anyways. Backup does not work. I gave the full file path to the back up folder then restarted the browser and found nothing. Exporting your settings is the only one that works. The ability is to sync doesn't seem there either. "Sync auto save sessions" being checked by default doesn't seem to sync anything. "Enable Cloud Sync" is appended with "(Beta)". So there doesn't seem to be a way to reliably store your sessions to use them between devices using Firefox. Google Drive stores general files so I don't understand how Google Drive can be used to sync sessions between devices and browsers running the same extension. I use Firefox Nightly. There is also no way to simply add a tab to a session which may be on another window. You must copy and paste the URL to the window you want, then rewrite the session to group that tab with the ones you want. Overall, it is good, but unless if you are only using one browser on one device, the ability to backup, export, and sync really lowers the score for me.

when restoring sessions, the pinned tabs get messed up, they end up in different tabs whic h i need to move it back to where i want. Dont know if this is related to Container tabs of Firefox

Since some weeks ago, it's not saving on browser exit. Still a good manager.

Cloud sync is useless. Neither saves sessions to Google Drive nor syncs with other computers.