(NOTE: I'm using Ubuntu 15.04 with gnome-shell (gnome 3). I assume there's some OS-dependence here; I'm not sure if this is linux-specific or gnome-specific or maybe os-independent.) STR: 1. View some full-screen content, e.g. this YouTube video: https://www.youtube.com/watch?v=tRlmP6xWdw0 ... or click "Launch Fullscreen" here: http://davidwalsh.name/demo/fullscreen.php 2. Wait for the "[site] is now full screen" notification to go away. 3. Adjust the volume using hardware keys or key-combo. ACTUAL RESULTS: - Adjusting the volume brings up an OS volume overlay for ~1 second, to show the current volume-level. - Just after this overlay appears, Firefox's "[site] is now full screen" notification returns, with no useful purpose. EXPECTED RESULTS: - No reappearing of the "[site] is now full screen" overlay after a volume-adjustment.

I can reproduce this in current Firefox release (41) as well as current Nightly 44.0a1 (2015-09-28)

This bug is actually a combination of bug 578265 and bug 1196588. Because of bug 578265, the browser window loses its focus when you adjust volume, and because of bug 1196588, we show the notification when the browser gets the focus again. Fix any of the two bug can close this one.

(In reply to Xidorn Quan [:xidorn] (UTC+10) from comment #2) > This bug is actually a combination of bug 578265 and bug 1196588. > > Because of bug 578265, the browser window loses its focus when you adjust > volume, and because of bug 1196588, we show the notification when the > browser gets the focus again. Fix any of the two bug can close this one. 1196588 seems highly likely to end up wontfix for security reasons; 578265 seems like the right fix. I would suggest making this bug a dupe of 578265.

Seems reasonable to me. Duping.