In Mate 18.04 the super key opens the application Menu. I would like to disable this keybinding but I cannot find it neither in the keyboard shortcuts menu nor with dconf editor.
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