Dear Maintainer,

Prerequisits:
P1. I installed "Panel Settings" extension in my gnome 3 at

https://extensions.gnome.org/extension/208/panel-settings/

and

P2. chose "Autohide". All fine. Then
P3. I fullscreened firefox with F11. Again, all is fine.
Actions:
A1. Pressed again F11 to exit fullscreen.
Outcome:
O1. Firefox exited fullscreen for about a second and then returned on its own
to fullscreen(as if I would have pressed F11 again - I did not and my keybord
is not jammed).
Expected:
E1. Firefox should have stayed in "non-fullscreen" mode after the second F11.
Workaround:
W1. I used Alt+F5 to unmaximise it and then maximised it again.
Notes:
N1. I noticed that I can "almost fix" in another way: I keep th mouse over
the one of my opened tabs.
I say "almost" because, (N1.1) after going to another window (with Alt+Tab)
and back the fullscreen is auto-instating again and because (N1.2) I must
press F11 several times with the mouse in that area because the hidden Panel
bar keeps  steeling the mouse to auto show itself...
N2. I must stress that the transitions to and from fullscreen, as unexpected
as they are, are allways done cleanly by firefox, that is, the 3 buttons in far
right corner (minmise,maximise and close) are shown if
fullscreen is on and the animation of the menu, navigation and "tab" bars
being hidden/shown is also playing OK.
N3. I also did try firefox with no extentions loaded, that did not help.
N4. If "Normal" is choosen in "Panel Settings"'s visibility, all is as
expected.

Sorry everybody,

This was a false alarm: I had an older extension in gnome that was supposed
to remove the title bar of maximized windows which was causing all this. I
replaced it with a newer one and now all is fine.

Please close this bug.

Again, sorry for the inconvenience.