AFAICT it doesn’t work like that. The canvas isn’t showing the view hierarchy, it’s showing the objects in the design hierarchy that you can reveal on the left. Of course, that represents the view hierarchy that will be created by nib loading, but that’s not happening at design/editing time.

I think your best choice is to eliminate the subviews, and do all the work in the parent view, using an internal “selected digit” mechanism. Your subviews aren’t so terribly complex that this is hard, just tedious.