A stile and rail forming a corner, are connected by a unitary corner connector having a first upright portion disposed in a channel of the stile, a laterally extending portion, and a second upright portion spaced from and extending in the same direction as the first upright portion and disposed in an opening in the rail spaced laterally from the stile. The first upright portion includes a shoulder and the channel includes a shoulder, with the shoulders being in engagement to lock the corner connector to the stile. The second upright portion includes a shoulder engaging a shoulder defining the rail opening to lock the corner to the rail. When the connector is an upper connector a member is adjustably connected to the second upright portion which suspends the connector to an upper track. When the connector is a lower connector, an elongated guide element is slidably connected to the second upright portion which guides the connector on a lower track. Other details to the corner connector guide element, and adjustable member are embodied herein.