RE: Need better doc of compilation mode

[Drew Adams]

    1. I just discovered this feature (yes, I think it's a feature)
    by accident:
    Click (mouse-2) a grep hit on the file name or line number, and the text
    that matches the regexp is highlighted in the source buffer.
    Click instead
    anywhere else on the grep hit and the whole line is highlighted in the
    source buffer. Nice.

    I see no documentation for this. The logical place to document
    it would be in the Compilation Mode node of the Emacs manual.

I was mistaken about this. The undocumented feature was from my own code(!).
I had forgotten that my code did this:

(setq grep-regexp-alist
      (mapcar (lambda (elt)`(,(concat (car elt) ".*") ,@(cdr elt)))
              grep-regexp-alist))