Jumping the fence

any idea why she jumps the fence?  boredom, fun squirrels outside?
 
One way to stop her would be to install an invisible fence inside the "real" fence and train her to stay in the yard. These things get a bad rap, but a dog properly trained on an invisible fence learns to not leave the yard boundaries no matter what. So you don't have to worry about fence-jumping, or gates left open, or digging under the fence, etc.

The reason she jumps the fence, I believe, is because she wants to be with me or just inside the house instead of out playing with the dogs.  I don't think she is bored cause they have toys outside and she has 2 other dogs to play with.
 
I never really thought of putting up an invisible fence.  We are in need of a new fence because i think this one is as old as the house and I never really liked metal fencing.  We are planing on getting a 6 foot fence, but I know if she really wants to jump that she could too.  It's not like I leave them out there all the time just for potty breaks and maybe half an hour to give me time to mop the floor without them getting in the way. (Pug likes to attack the mop)  We've also tried putting her on a runner but it only goes so far and when the other 2 go to far and she can't reach she starts to bark until they come back.  Other than the invisible fence is there a way to train her not to jump the fence?  Thanks for all the help, this is my first big dog while living in the city.