Don't understand options to scan in a folder

I think the following summary description may be more understandable...(?)

(1) File-info (all) + file-contents (specified types)
(2) File-info (specified types) + file-contents (specified types)

Specifying additional file types does not work as I had expected. I wanted X1 to index the contents of C source and header files (*.c and *.h files).

I tried the following (without quotes):
"*.C, *.H" - does not work
".C, .H" - does not work
"C, H" - works correctly

Hopefully this will help someone - it is not described in the online help.

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