With the following object graph I am receiving the message 'ParentType PO has no child collection PODetailList' when attempting to enable 'Reject Duplicate Items' on the PODetailList. You can see in the following screen capture PODetailList is a child
collection of PO. I've even tried changing the child property name to 'PODetailList' but still getting the message. What am I doing wrong? I'm using version 18.104.22.168272.