OK, for my own sanity...
I am trying to make a custom view and wanted to start with the "Wall Detail Set" layerset, and duplicate making my own set called "CUSTOM WALL DETAIL". Apparently you can't make a layerset off that original set and then add say - "Walls, Foundation" to be visible - something is hardwired there by CA to NOT allow that layer to be viewed even if it shows as being on?? Nothing I can do allows me to make the foundation viewable in a derivative of that layerset.