It didn't work at all before unticking 'Use bookmark name as tab title' from options (I don't know why that is, but FWIW none of the tabs I have renamed have been bookmarked). After that it's been working 100%. I'm assuming some/many of the 1 star reviews might be due to the same issue.

Tabs remain renamed after restarting Firefox, that's what I expected the most!
Little problem : the tab which is active while closing the program loses it's name when restart. The other ones keep their name. So I always close Firefox after opening a random tab, but it would be good to fix this bug.
Could be improved : a shortcut to open the renaming dialog box
Could be great : a functionnality to automatically rename a tab using a specific part of a web link, or a specific text (always at the same place) of a page.

Little regrettable. i want to rename all tab allways.

Exciting idea but could be improved:

- option to change favicon
- set it working permanently even when we close tabs and quit Firefox