From Xojo Documentation
| This item has been deprecated since version 2018r4 and should no longer be used.
There is no replacement for this item.
The name of a Field in the table referenced by the DataSource property.
Relevant only if the PopupMenu is used in conjunction with a DataControl to display the contents of a field in a database table.
The following specifies the DataSource and DataField for the control. You can also set these properties in the Properties pane