Workflow metadata

If you want to use metadata to influence the Visible, Read Only, or Label property for the Group By Columns, the field specified as the Group By field must be a reference field (i.e., a locator, classification, or smart object). The metadata defined on its reference instances will be used to determine the Visible, Read Only, or Label properties for the Group By Columns. The data definition for the referenced object must include the Group By Column fields. Use a Modify Metadata task in a workflow to change the Group By Column metadata on the Group By Field value records.

Labels changed via instance data are not translatable.