The sliding side door can only be closed or fully open. In between if on a slope the door will gravitate through its own weight to the front of the vehicle or the rear. There is no fixed in between stop. The half-stop I've seen talked about seems elusive and will only stop the door going one way past the stop. It doesn't hold the door. The big problem therefore is if you have the rear window open and then open the sliding door without thinking ... sliding it into the open window! Could be expensive. Has anyone had experience of this problem and how have you resolved it?