Im glad to the 3dsen file being used. I'm happy you are enjoying it. The candy disappearing is part of the game if you collect a single candy in the room and you leave they will all disappear. This is due to to the nes being limited on how it handles background tile objects. It's also to prevent going back and infinitely collecting candy. There are some in game achievements at the ending for collecting a lot of candy and or finding hidden objects.