   :group 'Highlight-Characters :group 'faces)
 
 (defvar hc-highlight-wide-space-p nil
-  "Non-nil means font-lock mode highlights TAB characters (`　').")
+  "Non-nil means font-lock mode highlights wide space characters (`　').")
 
 ;;;###autoload
 (defalias 'toggle-highlight-wide-space 'hc-toggle-highlight-wide-space)

(set-face-background 'hc-tab "DarkGreen")
(add-hook 'font-lock-mode-hook 'hc-highlight-tabs)
(add-hook 'font-lock-mode-hook 'hc-highlight-trailing-whitespace)

;;;###autoload
(defface hc-wide-space '((t (:background "PaleGreen")))

    (font-lock-remove-keywords nil '(("[　]+" (0 'hc-wide-space t))))))

(add-hook 'font-lock-mode-hook 'hc-highlight-wide-space)

;; ---------------- zero width spaces

;;;###autoload
(defface hc-zero-width-space '((t (:background "PaleGreen")))
  "*Face for highlighting zero width spaces (`​') in Font-Lock mode."
  :group 'Highlight-Characters :group 'faces)

(defvar hc-highlight-zero-width-space-p nil
  "Non-nil means font-lock mode highlights zero width spaces characters (`​').")

;;;###autoload
(defalias 'toggle-highlight-zero-width-space 'hc-toggle-highlight-zero-width-space)
;;;###autoload
(defun hc-toggle-highlight-zero-width-space (&optional msgp)
  "Toggle highlighting of zero width spaces, using face `hc-zero-width-space'."
  (interactive "p")
  (setq hc-highlight-zero-width-space-p  (not hc-highlight-zero-width-space-p))
  (if hc-highlight-zero-width-space-p
      (add-hook 'font-lock-mode-hook 'hc-highlight-zero-width-space)
    (remove-hook 'font-lock-mode-hook 'hc-highlight-zero-width-space)
    (hc-dont-highlight-zero-width-space))
  (font-lock-mode) (font-lock-mode)
  (when msgp
    (message "zero width spaces highlighting is now %s" (if hc-highlight-zero-width-space-p "ON" "OFF"))))

(defun hc-highlight-zero-width-space ()
  "Highlight zero width spaces (`​')."
  (font-lock-add-keywords nil '(("[​]+" (0 'hc-zero-width-space t))) 'APPEND))

(defun hc-dont-highlight-zero-width-space ()
  "Do not highlight zero width spaces (`​')."
  (when (fboundp 'font-lock-remove-keywords)
    (font-lock-remove-keywords nil '(("[​]+" (0 'hc-zero-width-space t))))))

(add-hook 'font-lock-mode-hook 'hc-highlight-zero-width-space)
