Abstract: A chair including a seat support, a seat movably supported on the seat support for movement between a raised position permitting sliding depth adjustment of the seat and a lowered position preventing adjustment, and a detent device for securely holding the seat in the raised position while the seat is being slidable adjusted. A rack is formed integrally on or attached to the bottom of the seat shell. The detent device includes a seat support bracket attached to a top of a chair control, and a pair of moldings attached to opposite sides of the bracket. The moldings each include upwardly facing teeth for selectively engaging the racks to hold the seat in a selected, depth adjusted position. A resilient finger on each molding is adapted to engage a ridge on the seat shell for selectively holding the seat in either a raised position or in a lowered position.