Hide "Pilot active" controls in viewport windows

I want to have a viewport with no controls in it. To this, activate “Game View”, then go to “Settings” and enable “Hide Viewport UI”.
However, I need to pilot a camera, and as soon as I pilot the camera, I get this toolbar in the Viewport window:

Is there a way to hide that? Is there a Editor Setting I missed? If not, does anyone know a method to hide this without modifying the engine source code?

maybe start by this
actor = unreal.EditorLevelLibrary.get_selected_level_actors()[0]

Thank you, that’s a good idea. I tried it, unfortunately the message still appears and remains.