The auto reset is only in the forward position not in the rear position.
This was first introduced by the L.C. Smith Gun Company, Syracuse, N.Y. around 1887. It was put there for trap shooters who forgot to push the safety forward when calling for the bird and therefore lost the bird.

It is a scary thing to be walking around with a safety in the off position and not realizing it. With the bar horizontal it would let the shooter know this and flip it.

David