
After installing it, I found that the handle still wouldn't catch about half the time when it was unlocked. The sliding mechanism was sliding on top of the other metal part on the left that twists to pull the two latch rods, rather than fitting in to the groove. What I finally figured out was that the metal part that's highlighted with the red arrow has to push somewhat tightly down on the slider to keep it in place. Not so tight that it binds, but tight enough to keep it from flopping around. With the correct tension, it works right every time - at least so far
Hopefully this will help someone down the road.
