;; Font lock settings
(defface my-face-r-1 '((t (:foreground "gray" :underline t))) nil)
(defadvice font-lock-mode (before my-font-lock-mode ())
  (defvar my-face-r-1 'my-face-r-1)
  (font-lock-add-keywords
   major-mode
   '(("\t" 0 my-face-r-1 append))))
(ad-enable-advice 'font-lock-mode 'before 'my-font-lock-mode)
(ad-activate 'font-lock-mode)