tags such as [tag]."
(let ((subject (or (rmail-get-header "Subject" msgnum) ""))
(regexp "\\`[ \t\n]*\\(\\(\\w\\{1,4\\}\u00a0*[::]\\|\\[[^]]+]\\)[ \t\n]+\\)*"))
+ (setq subject (rfc2047-decode-string subject))
;; Corporate mailing systems sometimes add `[External] :'; if that happened,
;; delete everything up thru there. Empirically, that deletion makes
;; the Subject match the other messages in the thread.
(if (string-match "\\[external][ \t\n]*:" subject)
(setq subject (substring subject (match-end 0))))
- (setq subject (rfc2047-decode-string subject))
(setq subject (replace-regexp-in-string regexp "" subject))
(replace-regexp-in-string "[ \t\n]+" " " subject)))