Seems to be mostly good for me. Few minor issues though.
This secondary dialogue is overlapping here.
Switching the video resolution setting seems to take a little bit to kick in.
Sometimes when I switch video quality I get this vertical bar on the right end of the video
You have to click exactly on the seek bar to get it to seek. Clicking just a little too high or too low won't register a hit. Not a huge deal, but it can be a little confusing.
Firefox 57.0.2 on Windows 10
Overall seems to be working quite well. Thank you guys!