The Adopt Fields option allows the EasyCatalog fields placed on a document to be linked to a new data source.
The new data source must contain fields with the same names as the original document.
Choosing All will link all fields within the current document to a new data source.
Choosing Current Layer will link all fields on the current layer within the current document to a new data source.
Choosing Panel Selection will link all fields currently selected in the EasyCatalog panel to a new data source.