I have two walls that won't show up an a few sections. There are other walls of the same family which show with no problem. The only unique qualities of these walls seem to be that they have openings cut in them by means of a profile edit. It just so happens that they don't show up in the sections which cut through the openings. So if the section is cut through a portion of the wall that doesn't have the opening it shows up just fine. What am I missing?