Rated 1 out of 5 stars

Unfortunately, version 3.3.5 does not work in TB 102.7!
After pressing the ESC key, the note is closed and saved in the *.tmp file. "Alt+M creates a note or toggles its display. " - not true! Every time Alt+M opens a new note, the previously created note is never opened again!

This review is for a previous version of the add-on (3.3.5). 

1) Which operating system? If it is MacOS, it is not expected/guaranteed to work, because I have no way at all for testing.
2) Did you try disabling all other addons? There might be unexpected interactions.
3) Alt-M does NOT open the last viewed XNote. If you select a mail and press ALT-M, it opens an xnote window for editing. If you press esc (close the XNote window), you can reopen it, also on 102.7.0 with no other addons installed on Win, -> IF the email is still selected.
4) If you set options to not automatically display the XNote window, you can select an email and either open the XNote window (an existing or new one) with the button or with Alt-M.
5) If Alt-M does not work at all, TB might use those keys in your locale, or another addon might use it. In Extra->addons, use cog wheel, there is an entry where you can change the keys for the shortcut.

I just tested all of this in a freshly updated TB 102.6->102.7.0 and all is working in Win 11.

If you still have problems, please give more information on the support page on github, technical exchange about problems is easier there than just by giving 1 star reviews.

1 star reviews are for addons not performing their function at all, and not for temporary problems coming up after an update, which might even be caused by other addons or TB itself.