Pooched, for now... [resolved] Rated 5 out of 5 stars
Useful tool. Thank you. After recent updates, seems to be taking reloading conniptions (spinning circle), causing the add-on bar to dance like a drunk goblin, but only on Windows and only on one machine, so there is a conflict with a recently-updated add-on in conjunction with the update to 16.0.2 . Had to disable for now.
Disabling the add-on and restarting Firefox, then re-enabling and restarting FF again seems to have tamed the goblins.All good...