A molding assembly closes a gap between the track of a vehicle sliding door and a headliner that conceals a roof rail mounted air bag. The headliner has an edge that extends along the track but is spaced from the track to create a gap. The molding assembly includes a carrier and a flexible seal strip. The carrier carries a plurality of fastening clips that engage with apertures in the roof rail to attach the carrier to the roof rail. The flexible sealing strip has a stem that mounts on a leg wall of the carrier, a first arm that laps onto the edge of the headliner panel and a second arm that laps onto the track. The headliner bends downwardly when the air bag deploys and the first arm of the flexible seal strip flexes to permit the edge of the headliner to escape from the flexible seal.