Shower door not staying closed

[drhowell]

There should be a small black knob that also locks the door in the closed position. Often these get broke, especially if you close the door with the catch closed. I found them at an RV store when mine was missing.

I also found my door was dragging on the threshold. The corner glass on the hinge side would slip in and out of the channel molding up the wall. I pushed the glass into the channel until the door didn't drag and put a screw through the channel into the glass frame.