External HDMI TV not shown in Display Settings
Today I noticed (I assume this is some random change by Apple) that my external Sony TV is no longer shown in the Display Settings so I can adjust resolution and refresh rate. It works perfectly fine otherwise! but is stuck on maximum resolution with 30Hz, I would prefer to set this to lower resolution at 60.
Edit: I found the answer myself. For unclear reasons, when you set the display to mirror a window only, it disappears from Display Settings. Either I am stupid, or this is the stupidest UX decision ever, or a bug.
MacBook Air