Abstract: An apparatus for securing telescoping sliding panels, which are essentially oriented in parallel, vertical planes, against movement perpendicular to their sliding directions, includes a track, parallel first and second carriages which retain the lower edge of each panel and ride along the track, a lip projecting from the first carriage having an upturned free end, a lip projecting from the second carriage, having a downturned free end which extends between the first carriage and the upturned end of its lip. The carriage for each panel preferably includes a body portion which is tubular and has wheels mounted beneath it and gripping members projecting from the top of it for holding a vinyl channel which receives the lower edge of the panel. The track has an upper surface with channels recessed into it for guiding the carriages. An edge of the track is turned upward at a right angle to form a wall for retaining the carriages. The wall is provided with a lip described above.