Does a catalog.xml overwrite a document-local schema association?

It appears to me that once I configure a catalog.xml, this will overrule a binding via <?xml-model?> in the document. Is this true? If yes, it would be preferable if the local schema association would take precedence. We quite often work with documents in the same namespace for which having a general entry in a catalog.xml is convenient. Nevertheless specific documents - while using the same namespace - may require a different schema with extensions.

What I see: as long as I have no catalog.xml configured, the document validates just fine against the (extended) schema given in <?xml-model?>. If I add a catalog.xml, associating the namespace with a different, basic schema, the document is no longer valid.

In the outline I see both schema listed and I'd like to have the first applied, while in fact the second seems to take precedence:

Reproduce the behavior with a catalog.xml namespace mapping and a document-local association, then compare the schemas shown in the outline with the schema used for validation. Trace how the XML extension resolves these two associations; done means the documented precedence is implemented and the example document validates against the intended extended schema.