I'd like to color the messages in my *mu4e-headers* view, depending on which mailing list they come from. I'm rather new to emacs face alterations, and I didn't see anything that looked relevant for this. Are there programmatic hooks for defining a per-line face?

Example: If an email is in my INBOX/ML folder, I'd like it green. If it's just in my INBOX, I'd like it blue.

1 Answer 1


Line faces are defined in mu4e~headers-line-handler-functions. To change the face conditionally you can set your preferences in mu4e-mailing-list-colors and try the following code (based on the mu4e~headers-line-apply-flag-face function):

(defvar mu4e-mailing-list-colors
  '(("emacs-devel.gnu.org" . "green")
    ("emacs-orgmode.gnu.org" . "blue")))

(defun mu4e~headers-line-apply-mailing-list-face (msg line)
  "Adjust LINE's face property based on the MSG's mailing-list value."
  (let* ((ml (mu4e-message-field msg :mailing-list))
         (face (if (assoc ml mu4e-mailing-list-colors)
                   `(:foreground ,(assoc-default ml mu4e-mailing-list-colors))
    (when (fboundp 'add-face-text-property)
      (add-face-text-property 0 (length line) face t line))

(add-to-list 'mu4e~headers-line-handler-functions

enter image description here

For a more suddle effect you can add a new header field and add fontification only on that portion of the line. You will also have to add (:colorize . 1) to mu4e-headers-fields and tweak the numbers in add-face-text-property. Here's an example:

(add-to-list 'mu4e-header-info-custom
             '(:colorize . (:name "Mailing list"
                            :shortname ""
                            :function (lambda (_msg)
                                        (make-string 1 ?█)))))

(defun mu4e~headers-line-apply-mailing-list-face (msg line)
  "Adjust LINE's face property based on the mailing list."
  (let* ((ml (mu4e-message-field msg :mailing-list))
         (face (if (assoc ml mu4e-mailing-list-colors)
                   (let ((color (assoc-default ml mu4e-mailing-list-colors)))
                     `(:foreground ,color :background ,color))
                 `(:foreground ,(face-attribute 'highlight :background)))))
    (when (fboundp 'add-face-text-property)
      (add-face-text-property 53 54 face t line))

enter image description here

  • Thanks for the answer @jagrg! Unfortunately the color bar in the second solution disappears when your point is on a particular message. I think the highlighting is overriding it somehow. Any idea how to fix that? Jul 6, 2019 at 22:08
  • @MatthewPiziak can you try now.
    – jagrg
    Jul 7, 2019 at 20:48
  • Interestingly, it still doesn't show the full bar for me, but I can see the color in the underline: imgur.com/XX7lAnvl.png. Jul 8, 2019 at 1:17
  • I stopped mu4e-header-highlight-face from inheriting from region and now it appears. Not sure why, but my region has DistantForeground: gtk_selection_fg_color and Background: #11472b. Anyway, I find that removing the region inheritance looks cleaner with my configuration anyway, so I'm keeping that. Jul 8, 2019 at 1:19

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