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The reference field (aka record-picker field) in the details table when displayed read-only always displays the value of the key field in the corresponding master record. The key field in the case you cite above is the Record ID#. To display the address value from the master record that you see in the record picker you'll need to place a lookup field that looks up the address field in the master record. On the form you should place the address lookup field next to the record-picker field. In the custom form designer set the record-picker field's "Display when this form is used for:" property to:
set the address lookup field's "Display when this form is used for:" property to:
Now the address field will display when the form is used for viewing and editing.