No matches in *.h files, or any other file types than *.c (C-only project)

[MisterScott]

Not finding any matches in .h or other non-C) files (C-only project).
Edited the "in:" window contents to ".c,.h,*.py", etc. It only ever matches items in .c files.
Running in Eclipse 2021-09 (4.21.0), Build id: 2021-910-1417.
OS: per uname -1: Linux 4.9.0-16-amd64 #1 SMP Debian 4.9.272-1 (2021-06-21) x86_64 GNU/Linux