Abstract: Improvements to movable closure systems which aid installability and reliability of said systems can include wheels running along the top and bottom of individual slidable elements, the wheels oriented horizontally and disposed within a track configured for receiving the horizontal wheels. The horizontal wheels reduce the vertical profile of the track-engaging portions of the slidable elements, enabling more of the slidable element to be used for glass or other aesthetically-preferable transparent materials. A track leveling system enables installers to more easily deploy and properly tune the system between floors and casings which are not perfectly flush. A compression jamb permits closure of the system via slidable elements pressing into the jamb to deflect it in order to better seal the closure comprised of the individual slidable elements. A durable hinge mechanism permits the sliding elements to rotate in order to stack the sliding elements at one end of the system.