If i toggle fullscreen with double click the menu item Fullscreen does not toggle on/off.
So if i select Video > Fullscreen to go fullscreen, then double click to leave fullscreen, look in Video menu and Fullscreen is toggled on, even though the player is not in fullscreen.
Click on Video > Fullscreen will make it toggle off, and you have to select it again to make the player go fullscreen.
Using Windows 7 + VLC 2.2.1.