I didn't see that button until yesterday, a few days after I posted that. It's not in an obvious spot, It would be more helpful if it was also on the Design page an not just Mapping. I don't mind it opening the last collection but it needs to be clearer on how to change it.

Ah, the road map.

I took a look at the app and you’re actually seeing a bug. The Swiss Universe app was one of our launch partners and hasn’t updated yet to the latest build. We had a bug where in-app web views would open in the device’s last orientation, not the app’s locked orientation. This was addressed in our release on August 3rd and now in-app web views open in the app’s locked orientation.Neil