A vertically operating door and its drive system can be configured to push a door panel along a track to various overhead storage configurations including vertical, horizontal. inclined and coiled. Semi-flexible drive strips extend continuously along lateral edges of the curtain. The system includes a drive gear that engages a series of projections on at least one drive strip so that the gear can push the door between its open and closed positions. To protect the door from being damaged by collisions, the track can include a breakaway feature that allows at least a portion of the panel with its drive strip to separate from the track without permanent distortion. The drive strip and panel remain together as they break away from the track. The threshold of the breakaway force can be changed by selecting a retention strip from a plurality of interchangeable strips having different degrees of flexibility.