Bloody brilliant stuff. Thank you :)

amazing. bugged me at the end of december, re-installing fexied the issue. very good app otherwise

Works really well, although need to understand settings and that Firefox now has a similar feature biult-into itself, which saves users from many annoyances or even troubles.

Good to have both if closing browser with many windows happens often to you.

After may similar I tried, this one is most stable and for me do the job perfectly Thanks Sienori!

Useful addon.
Please create a sort function all tabs by url like
jkljlk.host1.url
jkljljgg.host1.url
jhg.host2.url
jhgjkh.host2.url

タブの保存に、素早く元のタブを開けるこのアドオンが大変便利です。
ただ、このアドオンのバグか、ほかのアドオンの影響かはわかりませんが、現在のウィンドウで開くと、一番左端にあるタブが、一番右端で開くようになってしまいました。
解決方法はありますか？

It does what it should and that very good for me since 2 months.
But when restarting FF and opening last session via Tab Session Manager the tab order ist lost. I did tests now by saving and reopen of a (one) window:
Reopening works fine when active tab is the most right one.
Atherwise only the tabs left to the active one are correct after reopening. The tabs to the right of the active one are reopened in wrong order.
What I found saving is not the problem it's the reopening !
Whould be nice to hear if you found that as i do and more nice if you would correct this issue.
kr johann