I had a horse (RIP Duke) that not only did this, he also figured out if he pushed his butt against the gate, at the end where it was chained, he could break the chain. -- I watched him break the second chain from the kitchen window, lollol
I had to buy a length of chain heavy enough to use to pull cars out of ditches:)
He would open his stall during the time I had to board him. The BO put a second slide latch further down the door, where Duke couldn't reach it.
The day the BO busted Duke, he had spent a good hour in an empty stall where he could watch Duke thru the cracks between wood slats.
When Duke opened his door and calmly sashayed down the aisle toward the back door, the owner popped out of the stall and said "Duuuuuke--- where do you think you're going!?" He said Duke's head shot up and he immediately put the brakes on. The BO was laughing so hard, he almost couldn't get the hay twine around Duke's neck to lead him back to his stall.
's Palomino, many years ago, my Arab/Saddlebred was one to crawl under the fence when the creek bed dried up in the summer, lollol
Both of my remaining horses' stall doors open in or out. They know which way to push those doors to get out facing the direction THEY want to go, lollol