People go to dog trainers all the time with specific problems, such as barking, recall, cat-chashing, and jumping on people at the door. Too often what they get is a dog "trainer" who takes them through basic leash obedience with lots of food rewards, but who never specifically addresses the problem that the client first presented with.
Why is that?
Simple: you do not stop internally self-rewarding behavior with treats. You stop such behavior with an appropriate punishment, something that a "pure positive" dog trainer may know little or nothing about. Get a trainer who knows how to do more than teach tricks and walk at heel.
** So You Need a Dog Trainer?
** The Sign at the End of the Driveway