XML Catalog Preferences

To configure the XML Catalog options, open the Preferences dialog box and go to XML > XML Catalog.

The following options are available:

You can also add or configure catalogs at framework level from the Catalogs tab in the Document Type configuration dialog box.

When you add, delete or edit an XML catalog to / from the list, reopen the currently edited files which use the modified catalog or run the Validate action so that the XML catalog changes take full effect.

Related information
http://xerces.apache.org/xml-commons/components/resolver/resolver-article.html#ctrlresolver
Working with XML Catalogs