I have a Nvidia eVGA GeForce GTX 680 and I am running three monitors off of it. Whenever I watch the live streams on twitch.tv and I want to watch in full screen via the little button on the bottom of the video, the full screen opens on a different monitor than the window it was running in inside of Firefox. Videos on youtube.com and the like open on the same monitor and are not a problem, it is only twitch.tv. Is there any way to fix this?
I don't have an answer, but I do have a workaround. Hit the "pop out video" button on twitch, then hit F11 (or go view>fullscreen) to make firefox fullscreen on whatever monitor you like.