I have the same problem with my Chihuahua so I have to keep her leashed at all times, even in the house since she likes to grab the tootsies out of the cat box and run. I've been trying to train her to come when called but she's being really stubborn. She'll have to learn eventually or else she better get used to living on a leash the rest of her life. She's just a puppy so hopefully she'll learn. I just couldn't take the chance of her running off when we're outside, this could be so dangerous for her.