Tried to create a rack with some gear. Somehow, stuff seemed to disappear, so I re-added it. Now I see there are supposedly, 17 modules but only 9 are actually visible and the visible ones are the only ones I actually want-- how do I find these invisible modules to delete them? They show up in the data sheet but the data sheet doesn't allow me to delete them there. Consequently, the power and price calculations are way off...