I am running GNOME 3.14.4 and I can't find what is the purpose of one of the bottom buttons in the GNOME system menu.The four bottom buttons can be used to, in order:Access system settings?Lock the screenRestart or power off the machineWhat does the second button do? It is a toggle control -- when clicked, its icon changes from a circled arrow to a circled arrow with padlock.  The first thing that came to my mind is screen rotation, but it's just a wild guess.
What does this GNOME button do?
gnome