The only issue I have with using this addon is that I can't use mouse gestures. I know it is a FF thing and not the addon itself but unfortunately it is a deal breaker for me ;(

The twitch chat won't show up. Instead I get a black screen with the twitch logo. This is odd because it works perfectly on Edge

Latest version does not work with latest Waterfox as it assumes the version is incompatible. Luckily changing the User Agent works as a bypass, but it's suboptimal.
Other than that it works great, but I'd like an option to change the fadeout timer on the UI elements as it is a tiny bit too long for my taste.