She's not charging, just doing a "front and center" move and "awaiting further instructions". That trait could be very advantageous in fact, as long as I can figure out how to move her around the pen when I want to. I guess I could always use a rope to slap the ground...
She had gotten quite pasture wild for awhile, and to break her from that I used the "rope on the ground" routine to chase her around the pasture for awhile until she got tired of it and came to me. I don't think that's what taught her the "front and center" move.
Voice commands (which Lightnening has learned quite well) are don't seem to work with Misty. That is actually what I wanted to teach her, but first I have to figure out how to get across to her what they mean.
Well, stand off of her shoulder, make sure that the whip if you are using one stays behind her and use the voice commands along with it. Praise her as soon as she does what you want her to. If she starts to come to you, call her to you, then pat her and start all over.
Just be very consistant, firm, and patient. By the way, don't work her too hard as long as she's nursing a foal.
Another thing, you should be working her on a line, not free until she knows exactly what you want. And the reason for calling her to you if she turns and comes is so that she associates that with a command to come or come here, instead of her choice. And try saying whoa if she starts to do that, then come here if whoa doesn't stop her on the fence.