User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Firefox/52.0 Build ID: 20170316213829 Steps to reproduce: this fade animation when you switch to Fullscreen for a video is making Firefox seem/feel slow. Something has to be done about it, shorten its duration or get rid of it altogether. No other browser does this long drawn out fade animation when you fullscreen a video. I could see people using another browser for a moment and thinking "wow this is so much faster than Firefox"

AFAIK, The fade animation is introduced by Bug 1160014

Ya, I remember reading that it's necessary for security reasons but does it have to be so long in duration? Surely it can be shortened a bit to make Firefox feel faster and more responsive (In reply to Alice0775 White from comment #1) > AFAIK, The fade animation is introduced by Bug 1160014