Field with no datasource or display method.

I’m looking at editing a form in Dynamics AX 2012 but am a little confused as the field I am meant to be adding doesn’t have a datasource or display method set.

I’m trying to add the purpose field from the LogisticsContactInfo form that is displayed when choosing “More options > Advanced” from the contact information grid in the suppliers form to the contact information grid. Usually this would be simple as I’d just find the source for the field and go from there however there doesn’t seem to be any source set for this field. Can anyone please point me in the right direction on how this field is retrieved and displayed?

I’ve found the solution to this. The field is populated through the creation of a lookup from a query that isn’t declared in the datasources of the form. I should be able to copy this over to the other grid now.