It appeared to be a glued connection. I reglued it with garilla glue. This lasted for about three uses, and it broke loose again. Is there a permanent fix for this poor design ?

Hi,
Well, you have to get rid of the old glue in order to get a bonding surface, but there is a type of epoxy made for plastic (Plastic Weld, or something) that will mutually bond the pieces.
Peace,
Clarke