1 files changed, 11 insertions, 5 deletions

diff --git a/lisp/mail/sendmail.el b/lisp/mail/sendmail.el
index 42d52af460e..faed238e239 100644
--- a/lisp/mail/sendmail.el
+++ b/lisp/mail/sendmail.el
@@ -212,17 +212,23 @@ actually occur.")
 
 (defvar mail-font-lock-keywords
   (eval-when-compile
-    (let* ((cite-prefix "A-Za-z") (cite-suffix (concat cite-prefix "0-9_.@-")))
+    (let* ((cite-chars "[>|}]")
+           (cite-prefix "A-Za-z")
+           (cite-suffix (concat cite-prefix "0-9_.@-`'\"")))
       (list '("^To:" . font-lock-function-name-face)
             '("^B?CC:\\|^Reply-to:" . font-lock-keyword-face)
             '("^\\(Subject:\\)[ \t]*\\(.+\\)?"
               (1 font-lock-comment-face) (2 font-lock-type-face nil t))
+            ;; Use EVAL to delay in case `mail-header-separator' gets changed.
             '(eval cons (concat "^" (regexp-quote mail-header-separator) "$")
                    'font-lock-comment-face)
-            (cons (concat "^[ \t]*"
-                          "\\([" cite-prefix "]+[" cite-suffix "]*\\)?"
-                          "[>|}].*")
-                  'font-lock-reference-face)
+            ;; Use MATCH-ANCHORED to effectively anchor the regexp left side.
+            `(,cite-chars
+              (,(concat "\\=[ \t]*"
+                        "\\([" cite-prefix "]+[" cite-suffix "]*\\)?"
+                        cite-chars ".*")
+               (beginning-of-line) (end-of-line)
+               (0 font-lock-reference-face)))
             '("^\\(X-[A-Za-z0-9-]+\\|In-reply-to\\):.*"
               . font-lock-string-face))))
   "Additional expressions to highlight in Mail mode.")