Sliding door operation?

Hi, should my sliding door latch in the open position to stop it sliding forward on it's own? I seem to think mine used to. If so, where is the latch mechanism (same as in closed position?) and where does it latch on to please?

Thanks.

Fronk.

 

yes, it should latch in the open position

the latch is at the rear of the door and 'clicks' to the latch under the track cover

 

If it used to latch open but now doesn’t this spring is probably missing: http://en.serial-kombi.com/-sliding-door-spring-1968-79-N34924.html