Using a debug build, 1. mkdir ~/px/ 2. firefox -profile ~/px/ y.html 3. Click the "full screen" button 4. Cmd+Q (quit while in full-screen mode!) 5. firefox -profile ~/px/ y.html 6. Click the "full screen" button Result: Firefox shows its in-window full-screen UI, but does not actually full-screen. Additionally, it hits an ObjC assertion failure, which is not fatal. 2012-04-02 01:46:25.244 firefox[93221:507] *** Assertion failure in -[_NSWindowFullScreenTransition makeAndSetupOverlayWindow], /SourceCache/AppKit/AppKit-1138.32/AppKit.subproj/NSWindowFullScreenTransition.m:671 2012-04-02 01:46:25.245 firefox[93221:507] Mozilla has caught an Obj-C exception [NSInternalInconsistencyException: Invalid parameter not satisfying: _transitionedWindowBeforeContents != nil]

Presumably related to this lovely bit in localstore.rdf: <RDF:Description RDF:about="chrome://browser/content/browser.xul#main-window" screenX="0" screenY="0" width="1680" height="1050" sizemode="fullscreen" />

This is known and sort of being worked on in bug 714911 (which landed with lion fullscreen, but got backed out). Ideally we'd stop persisting sizemode=fullscree entirely You'll hit the same bug on Linux and Windows, though you obviously won't get an ObjC exception.

The assertion from comment #0 happens when Firefox tries to put an invisible window into fullscreen mode. See bug 752294. Persisting sizemode=fullscreen isn't the only way to get this error. (You don't only see it when restarting FF with a sizemode=fullscreen window.) You also see it when you close the last window, that window is fullscreen, and you click on the FF Dock icon (which then tries to open a new window in fullscreen mode). So bug 714911 won't really be a fix for this bug.

I imagine the Gecko bug that triggers bug 752294 is also the underlying bug here: When opening a new fullscreen window, cross-platform code (nsGlobalWindow::SetFullScreen()) tries to make the window fullscreen before it's been made visible (before nsCocoaWindow::Show() has been called on it).

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046 Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5. If you have questions, please contact :mdaly.