Youtube full screen not full

[willcycle]

I noticed a new behavior in Firefox Developer Edition (it began about three updates ago). When I view a Youtube video in full screen mode it goes to full screen but creates a window in the upper right hand corner of my monitor taking u[ approximately 3/4 of the screen instead of the whole screen. When I view the video in Chrome it stretches to the entire screen as Firefox once did. I cannot find any way in Youtube settings or Firefox's to fix this. I have not changed video drivers and my monitor's resolution is 1980 X 1200. Any ideas? Is this a new bug?

[smsmith]

I believe this is a known issue. See this thread.
http://forums.mozillazine.org/viewtopic ... &t=3044714

And, I am moving this to the Builds forum, as it is more "proper" there.