Product review (3 stars): Won't stay in
This is the third one I have purchased (not from this seller) and it is the same story, so I think it is something wrong with my dishwasher. It is almost as if the threads on the hole in the door are stripped which will not allow the fill cap to go in the way it should. The dishwasher came with my home purchase and had a different cap that kept falling out which eventually fell off during a cycle and melted on the bottom heating element. I liked that one best because it had a "see thru" plastic "push button" type center that I could see how much rinse aid was left.  I couldn't find a replacement like that so ordered a fill cap "aftermarket".  That, too, never fit quite right and also fell out and melted from the heating element.  This was my last ditch effort and it fits the same as the previous one, so I think it's a matter of time before the same thing happens.