Hello, firstly sorry for my bad english. When there is for example youtube video playing in one tab, and in another tab there is video that just loads, (it can be muted), for example facebook video, or video on news site, the youtube video pauses for like a half of a second and continues to play afterwards. It gets really annoying when I am listening to music and just browsing facebook. I have tried "refreshing" firefox, reinstall it, I tried some addons, nothing helped.