jamesqf, you need a FIRM "STAND" command, which means HORSE, your feet stop NOW, and they do not start until I say so. On the ground, in the saddle, getting on, getting off. It is different from Whoa, which means stopping from a gait. And don't use "whoa" when you mean walk. (the girls that ride with me are bad about this).
I rarely tie my horses, because this ground tie/stand is so important to me. I hitch my horses to the carriage in the barn aisle, or outside the barn, and they need to not move ONE foot, or kick at flies, or swing their head around. These little things that we let them get away with build into big problems without us even realizing it.