I am replacing the handleset on my front door. The thumbpress on the old one no longer fully retracts the latch (similar to the problem shown on ). I am installing a Weiser "Welcome Home" Heritage handleset. However, I have this extra part that came out of the box and I don't know where it...

We have an old Mortise handleset on our front door. One with a handle and thumb-press on the outside and a door know on the inside. The problem is that the inside doorknob completely pulls out of the door if you pull on it. The knob itself pulls out as well as the stick part that goes into...