How can I disable Super Key in ubuntu-mate 18.04?
Solution 1:
On my clean installation of Ubuntu MATE 18.04 LTS the following commands
disabled left Super / Win key:
gsettings set org.mate.mate-menu hot-key ''
gsettings set com.solus-project.brisk-menu hot-key ''
If you want to get it back - the default value for both keys was 'Super_L'.