Reproducible with: Firefox 32 Beta 6 - BuildID: 20140811180644 Latest Firefox 33 Aurora - BuildID: 20140813004001 Latest Firefox 34 Nightly - BuildID: 20140813030201 Environment: Windows Vista x64, Windows 8 x64, Windows 8.1 x64 - could NOT reproduce the issue on Windows 7 x64 Steps to reproduce: 1. Open Firefox with a new profile. 2. Open a New Window (<Ctrl> + N). 3. Navigate to a page with a video of some sort (http://goo.gl/nQI91A). 4. <ALT> + <Tab> to some other application window (e.g. Skype), and then back to the new Firefox window. 5. Select the video's full screen button ---> Video opens in full screen as expected. 5. Press the full screen button again (or use the Esc key) to exit full screen mode. Expected results: Video exits full screen, and the Firefox window with the video remains in focus. Actual results: Video exits full screen, but the Firefox window with the video is now out of focus. The application window from step #4 (e.g. Skype) is now in focus as it displays over the Firefox window. See http://www.screencast.com/t/tkc2mzsLOi. Notes: - the issue is a regression from Firefox 29 (it does NOT reproduce in Firefox 28 or earlier, but reproduces in Firefox 29.0.1 and later). - the issue reproduces with multiple video pages (http://goo.gl/whqLoR, http://goo.gl/QA0tdD, http://goo.gl/CZXxPQ), but does NOT reproduce for Youtube videos.

This bug is not only for HTML5 video fullscreen but also Element Fullscreen. Steps to reproduce: 1. Open Firefox[A] with a new profile. 2. Open a New Window[B] (<Ctrl> + N). 3. Open attachment 574011 [details] 4. <ALT> + <Tab> to some other application window[C] (e.g. Skype), and then back to the new Firefox window[B]. 5. Click "full" button ---> A element is in full screen as expected. 6. Press Esc key) to exit full screen mode. Actual Results: window[C] is focused and top most. Expected Results: Firefox window[B] ahouls be focused and top most. This is a implementation bug of Bug 545812 since Firefox9.... Regression window(m-i) Not implimentated DOM Fullscreen API: http://hg.mozilla.org/integration/mozilla-inbound/rev/81ebc148aad3 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0a1) Gecko/20110904 Firefox/9.0a1 ID:20110904121620 Bad(implement DOM Fullscreen API, foece set full-screen-api.enabled = true): http://hg.mozilla.org/integration/mozilla-inbound/rev/d7cd9750988a Mozilla/5.0 (Windows NT 6.1; WOW64; rv:9.0a1) Gecko/20110904 Firefox/9.0a1 ID:20110904134605 Pushlog: http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=81ebc148aad3&tochange=d7cd9750988a Bug caused by Bug 545812

Removing keyword since Alice provided the regression window. Thanks Alice!

Another scenario for this same issue I believe, in Firefox 33.1.1: 1. Open Firefox with a new profile. 2. Go to http://www.youtube.com/html5 and make sure the HTML5 player is set. 3. Go to a youtube video (make sure it's in HTML5). 4. Go to Tools->Web Developer->Browser Console. 4. <ALT> + <Tab> to some other application window (e.g. Chrome), and then back to Firefox. 5. Select the video's full screen button ---> Video opens in full screen as expected. 5. Press the full screen button again (or use the Esc key) to exit full screen mode. Actual results: Video exits full screen, but the Firefox window with the video is now out of focus. The application window from step #4 (e.g. Skype) is now in focus as it displays over the Firefox window. This reproduced in Windows 8.1 x64... NOT reproducible on Windows 7 x64, just as for the original scenario.

It happens when exiting either fullscreen mode or DOM fullscreen.

Comment on attachment 8559537 [details] [diff] [review] patch Approval Request Comment [Feature/regressing bug #]: bug 688929 should be the fundamental reason [User impact if declined]: users continue to experience the window losing focus when they exit fullscreen [Describe test coverage new/current, TreeHerder]: no test [Risks and why]: AFAICS, no risk [String/UUID change made/needed]: n/a

Comment on attachment 8559537 [details] [diff] [review] patch We are late in the beta cycle and we have this bug for a while... It will ride the train with 37.

Reproduced the original issues (comment 0, comment 1 and comment 3) with Firefox 36.0.4 on Windows 8 x64. Firefox no longer loses focus in any of the 3 cases when using Firefox 37.0 and Firefox 38 Beta 1.