Why invisibility depends on the screen recording grant

The app’s setup calls this the precondition for the whole claim, and it means it literally: macOS will not let a window exclude itself from a capture it cannot see.

When the grant is missing the app says so on Settings › General › Permissions rather than behaving as though the window were hidden. Granting it is one visit to System Settings and one relaunch — see “Granting screen recording, and why it is required”.