Thanks for those responses. The solution you described does work (adding file-specific mappings and editing xtags.ini). :)

Since we do have thousands of these extensionless COBOL files, what I found most convenient is to edit the options for the default document type (as described in my earlier ...

The COBOL source code files in my workplace have no file extension. I would like for these to be treated in Zeus IDE as though they were of the existing "Cobol Document Type". Is this possible?

What I've tried so far is:

open a file that does in fact have the .CBL extension
go to Tools > Options ...