This add-on is, at the moment, a absolute disaster. I've never seen such a non-functional mess like this. How many month are there developer/beta/previous versions of Firefox 57? And now, at the last minute, the developer noticed, that he should do some programming, and delivered us THIS?
I know, that the most of this add-ons are developed as hobby projects. But only to say "Yea, my add-on runs on Firefox Quantum" you should NEVER do this to your customers/fans.
This add-on is (with Firefox 57) completely useless. 1 Star is way too much for this.