User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.13 (KHTML, like Gecko) Chrome/9.0.597.98 Safari/534.13 Build Identifier: Mozilla/5.0 (Windows NT 6.1; rv:2.0b12) Gecko/20100101 Firefox/4.0b12 Unable to enter full screen while playing webm video Reproducible: Always Steps to Reproduce: 1.Load http://www.youtube.com/html5 and select "Join the HTML5 beta." at the bottom 2.Now load http://www.youtube.com/results?search_query=trailers&aq=f&webm=1 3.In the list of videos that appears, click any of the video and start playing 4.Now click full-screen button at the corner of the video to enter full-screen Actual Results: Unable to enter full-screen Expected Results: full-screen

Did you tried with nighty build? http://nightly.mozilla.org/ I cannot reproduce with nighty.

Wasn't Youtube limiting WebM Fullscreen to "Content View" Fullscreen as opposed to Flash Usage where it is true Fullscreen? FWIW, I see no Difference in Google Chrome 11.0.672.0 <-> Fx 4 Trunk Behavior.

They override our "Full Screen" right-click context menu, and until the Full Screen API is supported in Firefox, there's no way for them to provide that via a button.