Well, if Autodesk would make it easier to see the color white as a graphic override then the problem would have been solved much faster. See below:
Notice how difficult it is to see that there is a "white" color override on the Topography category? I suggest either inverting the cell or simply showing the word "White" in the cell.
So next time you can't figure out why you don't see the outline of an object here is another possible place to look...