Gary
I helped someone else rest their sliding bedroom door. What happen to him was he forgot to secure it when traveling and it slamed back and fell off the track. It is sort of hard to get to but we got it back on track. We did not find the stop but did put a screw in the bottom of the door so it roll all the way back and off the track.
On the top of the door there are rollers. Turn the plastic lock on the rollers and allow the door to slide off the rollers (He had a roller fall off). We slid the rollers back on the track then slid the door on rollers then put a screw in the bottom of the door so it would not go back far enough to slide off the tracks..
Hope this helps.
PS.. we used a metal yard stick to hold the roller, reach way back to the edge of the track then pull it up to slide the door on..