your relationship appears to be a number (primary key) in AR Purchase
and text (foreign key) in PurchaseLineItem.
these should be the same type for one-one relationship.
I changed my primary key type to "text" in AR Purchase to match the foreign key in PurchaseLineItem.
But the problem is still there. What should I do next?
Never mind. I found out what the problem is. It is because my field's boxes were too big the overlap the 2nd row of portal. That's why prevent me adding item on 2nd row.
Thank you for trying to help though!