Reproducible on: * Nightly 36.0a1 (2014-11-11), * Aurora 35.0a2 (2014-11-11), * Firefox 34 Beta 8 (build1 / 20141110195804), * Firefox 33.1 (20141106120505). Affected platform(s): Windows 7 64-bit, Windows 8.1 64-bit. STR: 1. Launch Firefox with a clean profile. 2. Enter full screen by pressing F11. 3. Click menu → Customize → click Title Bar from the bottom of the palette → click Exit Customize. 4. Exit full screen by pressing F11 again. Expected result: The Title Bar *is not* visible while in full screen and visible once you exit full screen. Actual result: The Title Bar is not visible in windowed mode although it appears as enabled in Customize. Additional notes: - This issue is not a recent regression, as I managed to replicate it all the way back to nightly builds from 2013.