http://youtu.be/IyMMyq4L9qQ
The first video where you saw that this Dog stayed outside when the sliding glass door opened, might have given the impression that this is the only behavior this dog has learned in context with that very picture.
Now the second video shows that he has one signal to stay out, which is when the door opens, and another one that invites him to do what he really wants, coming in.
The signal in this case is “YES”!
Absolute control over the dog by making him do one thing (staying out), and providing positive reinforcement for that by letting him do the other (coming in).
Remember your mother used to say “eat your vegetables, then you can eat the cake”