Sharlette LOVES to be outside. Not a big deal except we live on the gulf coast in south texas... I live like a block from the beach... my yard is sand... Sharlette is already a skilled digger... I worry she may dig under our fence so I let her out under my close supervision in the back yard ONLY. She has started when ever the front door opens DARTING as fast as she can to it and out it if she gets there before she is caught. I had to chase her little butt threw my front yard this morning and dive to catch her. I DON'T LIKE THIS! My mother has 6 darter dogs and they are not fun to try to round up when they dart. My chihuahua is not a darter and can be trusted off a lead at any time. she will stay by me and never run off. I want Sharlette to be the same. My mom took all her dogs to puppy training and everything NOTHING helped the darting. does anyone have any advise?