Abstract: A horizontally sliding door includes a resilient retention system that helps hold a door panel tightly against its seals when the door is closed, and resiliently releases the door panel when an external force displaces the panel beyond its normal path of travel. If the door panel is displaced off its normal path, the resilience of the retention system or simply opening and closing the door automatically returns the panel back to normal operation. The resilient retention system can be installed off the floor, so the system avoids creating a tripping hazard and avoids being damaged by nearby vehicles.