The levels is a fantastic feature! Thank you!
I have this problem though: I start a new project, draw a room (just a rectangle, nothing else), then add a new layer and do the same on that layer. Although I can see both rectangles under each other in the aerial view in correct order, the design view only displays the (greyed) upper rectangle when I am on the bottom level. It should be opposite, i.e., showing a level that is below, not above the currently selected one.