This bug occurs using Firefox and Mac OS X. I am using Firefox 30.0/OS X Mavericks.

Browsing Wikipedia on a Mac using Firefox in full-screen mode, I decide to open up an image in Media Viewer. I then open up full screen for the image in Media Viewer. After clicking or escaping out of full screen for the image, my browser is also exited out of full screen and turns into a smaller window. The expected behavior is that my browser stays in full-screen mode.

To reproduce:

1. Open up Firefox in full-screen mode on a Mac
2. Open up any image in Media Viewer. Let's say this one: https://en.wikipedia.org/wiki/File:Ant.jpg#mediaviewer/File:Ant.jpg
3. View the image in full screen by clicking the diagonal arrows in the top right
4. Exit out of full screen by either clicking the arrows again, or pressing the escape key
5. Your browser is no longer in full-screen mode

Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=66356