How to close full screen.

[E.R.Kooi]

Dear VNC'rs, being a long time user of VNC, but only intermittently and
irregularly using it, and having recently downloaded RealVNC version 4
beta, I have a small problem.
In earlier versions of VNC you could close full screen use of the viewer
with a hot key combination. When selecting full screen you got a message
how to close it later on. With version 4 beta no such message is shown
anymore. 

Question: When you use the full screen in the viewer, how do you close
it again. 
I now use ctrl-alt-del and end the viewer task, but I prefer the hot key
approach if available.

Friendly greetings from Eppo R. Kooi.