Okay folks..need advice. Gigi has been GREAT since day ONE with her litterbox use. No accidents, not even once. I clean the boxes religiously (one little one in her playpen and the large one out on the floor). The dogs sometimes get into the large hooded box before I do if I'm in the middle of something when Gigi poops. The box came with a door but I took it off. How do I wean her onto using the door without losing her good litter habits? I sure don't want to do anything to throw her off and destroy her perfect potty habits!!! Thanks