At the request of @Matt Panzer a wishlist item, spun off from a discussion thread.   Basically: I think confusion arises around what "structural objects" are, as defined for the purpose of section viewports and the various options in the "Advanced Section Properties" dialogue. But this wishlist item goes a little further I think. I am going to try and keep this concise to start with, partly to stop it being too confusing, partly because I'm running out of time to write this just now.