User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:12.0) Gecko/20100101 Firefox/12.0 Build ID: 20120328051619 Steps to reproduce: Navigated to https://www.mozilla.org/en-US/apps/, played the video on the page (work absolutely fine). Then pressed the full-screen button in the right of the controller overlay. Actual results: Firefox went into full-screen mode, but the video only took up a third of the screen. (Pulled to the left) Behind it was the parent page. The video seemed to want to stick to its original resolution. See my screenshot - a picture is worth a thousand words. Expected results: It should have upscaled the video to take up the rest of the screen (like most video players do in full-screen). The page should not be visible. (A separate issue, but when in full-screen mode watching a video, the chrome (tabs, URL box, search box) should be hidden like other other video players do - maybe should be an option)

Thanks for the report! I can reproduce on a Mac OS 10.7 nightly as well. I think I'll move this to Core and mention it in bug 730121 to notify the people responsible for the page.

This happens for me in [Mozilla/5.0 (Windows NT 6.1; WOW64; rv:14.0) Gecko/20120416 Firefox/14.0a1] too, so not Mac specific. I wonder if it's related to bug 745067.

This is not a regression, it's always happened as long as we've had a fullscreen API. Probably a bug in our CSS rules for :-moz-full-screen or :-moz-full-screen-ancestor.

Yeah, we should probably explicitly set min-width/min-height to 0 and max-width/max-height to none on :-moz-full-screen. Does doing that help?

Yes, that fixes this bug. Thanks bz!

Comment on attachment 615912 [details] [diff] [review] Patch Requesting approval to land on m-c. This is a simple fix to a CSS style sheet, so low risk.