How to restart mission in custom games?

Hey, I wanna train build orders against bot in custom games so I often need to restart map. But… When I go to menu, the “restart mission” button is grey (inactive). So I must quit mission and create new custom games over and over again. Is there any command or something to restart mission immediately?

Custom Maps aren’t 'restart’able. You must rehost from scratch.

… unless there’s something I do not know about.

Just Save at the start, and revert to that with Load.