I have taken a jewelers file and gently filed the raised edge on the retainer stub to give it more Tooth to grab the sheet metal hole, additionally I have added a match in the seam (Void) of the stub to create more (Outward) grip force, thirdly I have purchased an additional "SET" of retainer to replace the ones that have fallen off and lost over the years, I am NOT a Fan of the generic repop round versions and continue the battle of the Clips.
Jim