It sounds like you did well with the E-Collar. But to be accurate ... you solved a problem you did not have to have, by putting him in a position to fail.I'll tell my experience with shock collar on my first boxer.
I was having problems with her getting distracted at the dog park, and not listening to me. She was "boxing" other dogs, being dominate, and getting into snarling arguments with other dogs. Nothing too crazy, but the problem was that she completely ignored me when she got inside the fence.
I put on the shock collar, and after voice command didn't work, gave the tone warning, then shock.
I got her attention with the shock, and I think It was only twice that I used the shock. After that, the tone worked. I never had to shock her again.
Also, the tone wasn't needed for very long either. It was maybe two weeks later and the shock collar just rotted at the bottom of the dog toy basket. I can't find it.
Anyway, It was like magic with my dog. She got the point to LISTEN to me. And it wasn't like I needed to cause pain with the thing. The tone was the useful part of the tool.
I'll be honest, I bought a new shock collar. But it is still in the package, and I have decided not to open it until she gets older and gains more confidence. I'll probably not need it at all.
I just need to be more patient. Work with her some more. She responds treats and praise just fine.
I do appreciate feedback from the members here.
If you "want" to find a bunch of undisciplined, unruly dogs that "don't" listen to their owners ... just go to your local Dog Park. Pretty much the home of the undisciplined and the unruly ... and they bring their dogs with them.
And some dogs should not be at the Dog Park, and for the most part, those dogs owners know that. BUt there take is often "Hey my Dog's issues are not my problem, his issues are your problem. Let me know how it works out??
Most Pro's that deal with dogs with serious issues ... don't do Dog Parks. Dogs don't need doggie friends. All a dog needs ... is you. But if you must, known safe dogs only or Pack Walks if they are available where you are???
With Pack walks all dogs on leashes and owners that "care" are with them.
I don't trust other people and their dogs myself my moto is "You keep your distance, I'll keep mine ... "Thank You."
And the behaviours your Boxer displayed at the Dog Park ie play style ... yep that is what they do! And some dogs ... don't take well to being punched in the face, circled at high speed and being jumped on ... and they know only two ways to make it stop, run away or put an end to this crap with their teeth! Dogs don't dial 911, to settle disputes ... just saying.
But enough from me ... aww sorta, see the second link here from Leerburgh on Dog Parks. And if you do go see the article from Robin Bennett "On Three Dogs Who Should Not Be At The Dog Park." Just a heads up as it were.
And yes time and patience and be cautious with the "overuse of treats." You can't give a treat for everything she does right, every time. Make the use of treats random. If you get the treat thing wrong, it ramps the dog up for the treat and yet again ... they won't listen to you. But it sounds like your getting it ... you two should do well.