ピン留めしていないすべてのタブをソート対象にしている。
私の希望する動作は選択しているタブだけソートすることです

In every Firefox version I have ever used, ctrl-shift-o opens up the Bookmarks Manager. After installing this add-on, when I type ctrl-shift-o all I get is the Bookmarks Manager. No sorting of any kind is done to the tabs. Additionally, none of my PC keyboards has ever had a "command" key that I remember. I did try using the Windows key--but that didn't work either. If you're using this add-on with a PC and Firefox and it works for you, please tell me how you are getting it to work.

Is it working, especially for new tabs opened?

Does nothing at all. Can't use when there is no menu entry. Useless!