spray arm won't stay put, am I missing something? I have the arm and a push-in type pin, it clicks when I replace it but I find the assembly lying on top of the glasses every time I run a load. Looked at the part online and it shows 3 pieces but not sure where the other button looking thing would go. Couldn't find install instructions. Hate to order new parts when these look fine. Dishes seem to come clean ok but really think I should re-install upper arm, right?
Thanks for your help.
Katalina :)