Looks a pretty good add-on. However, not working on FF developer 52.0a2 (2016-12-19) (64-bit). Nonetheless could see the LT button on the upper-right bar, nothing but a blank panel appears when clicking the LT button....
1.0.10 has just been released and should fix the most prominent issue. Saving the preferences still does not work. Update 2017-04-15: everything should work fine now again with version 1.0.13
