Android auto split screen - change app?

[WhoKnows]

I regularly use android auto and today I used Car Scanner to monitor oil temperature - I've used torque pro for years but car scanner works with android auto so can be on the main screen.

Anyway, whilst I can open car scanner fine in android auto, I realised I want the split screen with Sat nav on one side and the car scanner on the other. When I put android auto in split screen it always has Sat nav and my music player app.

Is there a way to change the 2nd app away from the music player? I've tried pressing buttons like an idiot, and Googling for solution but with no luck so I'm guessing it is a limitation of android auto rather that the f type but thought I'd ask.