Does anyone know how I lock folders so that my 3 year-old can't keep opening apps that don't concern her? She and I share the device and she has a lot of entertainment and games, but even putting those on the first pages or in folders just for her doesn't stop her from opening my lists, books, and other not-for-kids apps. She's smart enough to know how to find things no matter where I hide them, so creating additional folders isn't the answer.