STR: 1. Toggle fullscreen mode for a tab or html5 video. 2. Unfocus Firefox (e.g. by alt-tabbing). Expected: Titlebar shouldn't render. Actual: Titlebar is visible. Note: I have the Aero theme enabled and the title bar renders with the Windows Classic theme.

Added a screenshot with 3 examples. In the first example, only 1px of the titlebar is rendered.

Is this bug in the correct component? Can I provide more information to help fix this bug?

Issue reported again in bug 1109224, for Firefox 35. Simple steps to reproduce (tried on Win 7 x64 with Firefox 35 Beta 8): 1. Open Firefox. 2. Toggle fullscreen (F11). 3. <Ctrl>+<T> to open a new tab. 4. Click inside the new tab page and wait for the top bar to disappear. 5. Press the <windows> key on the keyboard. Result: the windows start menu opens, and behind it Firefox displays with a Classic Theme titlebar overlayed on top of the page (see https://bug1109224.bugzilla.mozilla.org/attachment.cgi?id=8533859). If it doesn't reproduce on the first attempt, just try steps 4 & 5 once more.

It's possible to reproduce this bug in the browser's fullscreen mode (F11), HTML5 video and the fullscreen API. Because of this I believe it boils down to a bug in the implementation of fullscreen mode for Windows (bug 68136), please correct me if I'm wrong though. Marking as blocking bug 68136 for this reason.

I can only find reports on this issue from users running win 7, so this should probably block bug 474052.