Abstract: A top-hung sliding door or window system for mounting within an opening in a wall includes upper and lower longitudinal tracks mounted to the upper and lower edges of the opening. A top rail is mounted to the upper edge of the glazing panel and is suspended from the upper longitudinal track for longitudinal movement. Vertical rails are mounted to the vertical edges of the glazing panel. A bottom rail is supported on the lower longitudinal track for longitudinal movement. A bottom rail insert is mounted to the lower edge of the glazing panel and engages the bottom rail for vertical movement relative thereto. Vertical rail inserts affixed to the ends of the bottom rail and projecting upward therefrom are movably attached to the vertical rails. When the upper edge of the opening is displaced downward, the first and second vertical rails move downward relative to the first and second vertical rail inserts, and the bottom rail insert moves downward on the bottom rail.