Fix last change

* lisp/mail/rmail.el (rmail-simplified-subject): A prefix can have
up to 4 characters, not 3.

1 files changed, 1 insertions, 1 deletions

diff --git a/lisp/mail/rmail.el b/lisp/mail/rmail.el
index 6c9847304fd..40d34702e4e 100644
--- a/lisp/mail/rmail.el
+++ b/lisp/mail/rmail.el
@@ -3408,7 +3408,7 @@ whitespace, replacing whitespace runs with a single space and
 removing prefixes such as Re:, Fwd: and so on and mailing list
 tags such as [tag]."
   (let ((subject (or (rmail-get-header "Subject" msgnum) ""))
-        (regexp "\\`[ \t\n]*\\(\\(\\w\\{1,3\\}[:：]\\|\\[[^]]+]\\)[ \t\n]+\\)*"))
+        (regexp "\\`[ \t\n]*\\(\\(\\w\\{1,4\\}[:：]\\|\\[[^]]+]\\)[ \t\n]+\\)*"))
     (setq subject (rfc2047-decode-string subject))
     (setq subject (replace-regexp-in-string regexp "" subject))
     (replace-regexp-in-string "[ \t\n]+" " " subject)))