[Zope] ZCatalog questions

[Itamar]

1.  What's the difference between the Metadata tab and the Indexing tab?

2.  I understood from the draft CatalogAwareness how-to that editing a
propertysheet with the built-in interface doesn't update the catalog -
you have to do it manually.  Is it possible to check if an object
inherits from CatalogAware?  Because if so, I'd change Zope to update
the catalog automatically if the changed object was CatalogAware.

TIA.

Itamar S.-T., itamars@ibm.net