Paragraph Tag in Paragraph Designer, but not in the Paragraph Catalog

In the Paragraph Designer (Default Font property group), in the Paragraph Tag field, I have a paragraph format, Heading3C.

However, this Paragraph format does not show up in the Paragraph Catalog, even when the "Show All" option is selected.

How can this be the case?  How can I have a "Heading3C" paragraph format tag without it showing up in the Paragraph Catalog?

Note:  I do see a "Heading3" Paragraph tag in the Paragraph Catalog, but not the "Heading3C", if this is of any significance. I'm baffled.

Any body know how this can be the case?

Thanks.