Bin door has never been secure. It falls off every time we open the door.

Did nothing. The old bin had been repaired so many times just trying to make it stay in place that we threw the old one away and bought a new one. While at it, I looked to see if I had room for another shelf bin. I simply snapped it on too. The new door bin that I purchased does not stay on any better than the one I replaced. My summation would be that the little clips that protrude to hold it on are either too rounded and it slips off or they are simply not long enough. One bump and this bin is in the floor along with it's contents.