Ours is very similar. She is much more aggressive if she is on a leash. I have found that if we take her to the dog park, or if she is off leash, she is very shy around other dogs. She barks at everyone who walks by our house, and she definitely barks at all of the dogs that walk by. She also growls at men who come near me if I am holding her or if they approach my car (even the guy who put gas in the car). I guess that really isn't a bad thing though.
We just haven't been able to break her of the barking, and it is rather frightening when she barks at strange dogs while we are on a walk.
