Not sure if this is by design, but if you navigate to the lower floor in Platforms view (Shift 6 on PC) , then click on the Shapes button (Shift 1 on PC), ideally the game should return you to the default floor and enter Shapes view mode. What happens instead is that you stare at the inside of the floor. It was not too obvious at first what I was doing wrong, might be frustrating to players.