Use a Reusable Part
If this property is selected , the Framework will look for a reusable part when expanding an instance list entry at run time, otherwise it will look for a function.
The reusable part must have ancestor #VF_AC023. See DF_T3507 for an example.
The component signals the addition of new instance list entries using Signal uAddListItem
See Relationship Handler.
This property is in the Business Object Instance List/Relations tab.