Unable to hide the menu-bar icon

The menu icon takes precious space in my menu bar and I mostly never use it (I just use features via gestures).

I tried to disable it from Preferences but the setting “Menu”->“Show icon in the menu bar” is ticked and greyed out, so I cannot deselect it.

Why is that? How do I restore the setting and hide the icon?

This is only a feature of licensed copies of TotalSpaces2, it will be possible to uncheck if a license is present.