App does not show up on menu bar

[Boltzmachine]

From the activity monitor I can see the program is running. However it does not show up on the menu bar so I do not know how to control the behavior

The menu bar is not full because it still does not show up after I close some apps on the menu bar

[newmarcel]

This is indeed unexpected. Right now the default behaviour is to quit when you drag the icon out of the menu bar.

Do you use any third party menu bar managers? At least in your screenshot I don't see anything unusual.

Will the icon re-appear when you restart your Mac… or in the worst case when you delete the app and install it again (from the website or via homebrew)?

[Boltzmachine]

No I did not use any menu bar manager.

I tried restarting, deleting and reinstalling it through both website and homebrew. They don't work.