Welcome to the board.
At the risk of seeming very grumpy after a first post, though :lol:, I have to say that electric fences are controversial and really divide people.
Simply walking the dog on a leash, as you are clearly doing very successfully
, is far preferable to using an electronic fence I think -- for my own part at least, I would never home a dog to a situation with an electric fence for so many reasons. To start with, from working in rescue I've seen dogs wearing electric collars regularly in the pound -- if they see something they really want to chase, they will go right thru, get shocked, and won't cross the barrier to come back. It is really sad because many of these dogs are never reclaimed but obviously someone took the time to put one of those collars on... to no avail.
It sounds like you are using it mainly as a door barrier but be sure you know what the negatives are to their use. Electronic collars have been known to malfunction and burn thru the necks of dogs and also can cause behaviour problems. I always suggest anyone considering using one at least put it on themselves and set it on the *highest* setting. Then walk through the barrier to feel what the dog feels. Many people say they try the collar on themselves and are happy it isn't that strong, but forget the little zap they feel as a 150 lb person is not like for like to what a 15 lb cavalier feels -- we need 10 times the strength of that jolt and to have the collar on its highest setting.
If at all possible, I think it is always much better to train your dog to do a reliable sit and down and recall, while also making sure a door is never opened where she can bolt and having secondary screen doors, for example. I have a house that opens directly on to the street, and just watch the door. I've never had a problem; I just make sure the dogs never have the chance to go out the front door by closing them in behind other doors.
Some pros and cons -- the initial article is con, but many people posted on both sides of the issue:
http://www.dogstrust.org.uk/information/poppysopinions/shockcollars/