I use tons of terminal windows (gnome-terminal) all the time for various tasks. Thus, it's important for me to be able to go into full screen mode (F11) - if I need more attention or space and switch back later.
I haven't got any problem with this in previous Ubuntu versions, after "switching back" from fullscreen mode, I got the terminal window at its original place and size. However, after upgrading to Ubuntu 16.04 recently, if I press F11 to switch back, the terminal window is enlarged to cover almost the full desktop, it's not "full screen" anymore (that's OK), ie I can see panel, borders, etc, but still it's not the original size and position of the window. So I have to manually resize the window all the time.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: gnome-terminal 3.18.3-1ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic i686
ApportVersion: 2.20.1-0ubuntu2
Architecture: i386
CurrentDesktop: Unity
Date: Fri Apr 22 13:48:12 2016
InstallationDate: Installed on 2014-05-08 (715 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release i386 (20140417)
SourcePackage: gnome-terminal
UpgradeStatus: Upgraded to xenial on 2015-10-08 (196 days ago)
I've attached some screen shots, if it's more understandable than my not-so-perfect English, sorry about that.
Moreover, I had the suspect that it can be a generic window manager issue more, rather than gnome-terminal specific problem, but starting the KDE console (konsole) its fullscreen toggle functionality seems to be OK, just I have problem with the gnome-terminal, it seems.