Used to work alright during testing 10months ago, doesn't appear to work at all any more. The little window opens, and there are buttons, and there's a menu pull-down--but clicks on any of the options do absolutely nothing. I've tried removing and reinstalling the add-on, and restarting FF. Nada. Using FF 56.0 still, as I don't yet have options for all my add-ons that work with the newer FF.