its not possible since mg 3.12 to get to the desktop by pressing the windows key.
When you press the windowskey when MG is running, the taskbar is displayed, but game (or lobby or optionscreen) is still displayed. If you click something on taskbar the taskbar disappears again.
go to the MG-Gameserver-Lobby,
press windows key,
Close MG by using the return and exit buttons,
>>>> MG crashes after closing its screens.
3.12-dev is affected with this issues too.