Dynamic, well done to you!!
THAT is the only way to eradicate the problem and I do not care how good the horse is!!!
This is a hereditary, conformational, defect that would be passed on to the next generation.
It is very possible that your colt might grow out of this....there are great classes for geldings!!!
Sometimes Selenium may help, but only if the horse has a Selenium deficiency, sometimes supplements can help (and they also do absolutely NO harm and make the owner feel better...seriously!) but basically, this is an inborn problem.
He needs gentle, free, exercise- did you bring him up to wean him??
If so, he needs to go out, preferably with a quiet companion, or at the very least have a HUGE stall where he can walk around lots.