I've installed Linux Mint (latest as of today) and Ubuntu (latest as of a month ago), and both do NOT allow use of the Super key appropriately when going thru a TeamViewer session. Both environments are Hyper-V VM's, and both will allow the Super (ie. Window) key to do what it is supposed to do when access thru the Hyper-V terminal session.
Linux Mint will exhibit the Menu when the Super/Window key is pressed on the keyboard thru the Hyper-V terminal session. Ubuntu will show a search menu.
However, then accessing either of the environments via TeamViewer, neither will do anything when the Super/Window key is pressed on teh keyboard.
Would really love to see this working somehow, even if I need to map something manually.
Note that I've added this same content as a reply to the post at https://community.teamviewer.com/t5/Linux/quot-Win-quot-key-does-not-get-transferred-to-remote-machine/td-p/13560, but I was not sure if that full post would be ignored as it has been marked as "solved", when really it appears (to me at least) that it is NOT solved.
