''Please continue in your original thread - https://support.mozilla.org/en-US/questions/994511 - locking this thread'' I caugth and post on this link https://www.youtube.com/watch?v=8ttSGPOVEQw&list=UUQZVDNfROWrYXeIBLwo_K8w Same thing on Youtube, Facebook, Vimeo...all off videos in any site. Solved when restart Firefox, but it still happen again other time. I use Macbook pro 15, mac OS 10.8 I posted this question 2 times on: https://support.mozilla.org/en-US/questions/994511?esab=a&s=&r=0&as=s https://support.mozilla.org/en-US/questions/996646?esab=a&s=&r=1&as=s The guys help me, but not solved the problem. I NEED FIREFOX TEAM CHECK IT OUT, BUT NO ONES OF YOU CARE???