Rated 3 out of 5 stars

Allows me to use keyboard shortcuts on YouTube but after updating to Firefox 43, Flash doesn't load on other sites like this one: http://www.roosterteeth.com/episode/rwby-season-3-volume-3-chapter-6-fall

or this one: https://www.adobe.com/software/flash/about/

This review is for a previous version of the add-on (0.9.1-signed). 

It is fixed in new version 0.11.0 (both Focus Regainer and Focus Regainer Lite). Problem was because Mozilla changes some rules of security in Firefox 43. You are not correct: it was not work on any site with flash at all. You do not need this addon if you use Youtube with html5 player! =) Of course Youtube will always work because of html5. =)

Rated 5 out of 5 stars

It's working on Firefox 37.0.2. Works on YouTube and on flash games.

Focus Regainer won't work on YouTube when I'm using the "Ad Remover" function from the add-on "YouTube Enhancer Plus". However, if I turn of the "Ad-remover" it works perfectly while using YouTube Enhancer Plus. I can still block ads using Adblock Plus so I can still enjoy ad-free YouTube while I use Focus Regainer and YouTube Enhancer Plus.

This review is for a previous version of the add-on (0.8.1-signed).