I don't think there's any way to do something like that on OS X. Nor do I think it would change anything. The Touch Bar is controlled by the app with focus, not

I don't think there's any way to do something like that on OS X. Nor do I think it would change anything. The Touch Bar is controlled by the app with focus, not by its parent process. Process parent chains AFAIK have zero effect on communication with the Window Server (which is presumably how the Touch Bar APIs work).