Love it and FF/TB 12 Rated 5 out of 5 stars
Have used Foxclocks for ages and love it! Thanks!
Had to do a Windoze reinstall recently and when I updated FF and TB to version 12 and reinstalled my previous profiles from backup, Foxclocks was not visible in either, although the add-on bar was present (with other add-ons in it). Foxclocks showed in the add-on list, but when I went to disable it to see if it would come back to life upon re-enabling it, both FF and TB froze up and had to be restarted with Ctrl-Alt-Del (froze up separately - not both at the same time!). I then uninstalled Foxclocks and reinstalled it with a fresh download (not sure if the fresh download made any difference or not), and in both cases - FF and TB - Foxclocks was back with my previous settings and functioning normally.
So for those experiencing difficulties following the upgrade to FF/TB 12, try uninstall/reinstall!