Windows's key or Super L key can't be keybind for a custom command

Hi guys,

I try to keybind my Super L key (Mod key) to a custom command line but when i press Mod key, it seems like this key cannot be used for a keyboard shortcut. Every other shortcut works well with this command.
This key is not used by any other command so i don’t understand why i can’t use this shortcut.

Anyone else notice that ?

Thank you.

Super+<key> shortcuts work here under a Compiz environment. Not the Super key alone though, not sure if there is a technical reason for that?

I’m using the Super + Space combo to start synapse on a Logitech K120 here. I’m running Marco + Compton.

Oh ok thank you guys so under compton i can’t use Mod key alone for a custom shortcut. Thank you.