     (goto-char merlin-lock-point)
     (setq merlin-lock-zone-margin-overlay (make-overlay (point) (point)))
     (set-window-margins nil 1)
-    (overlay-put merlin-lock-zone-margin-overlay 
-                 'before-string 
-                 (propertize " " 'display `((margin left-margin) ,merlin-margin-lock)))))
+    (merlin-put-margin-overlay merlin-lock-zone-margin-overlay
+                               merlin-margin-lock)))
 
 (defun merlin-update-highlight-lock-zone ()
   (if merlin-lock-zone-highlight-overlay

                   (let ((overlay (make-overlay
                                   (merlin-make-point (cdr (assoc 'start err)))
                                   (merlin-make-point (cdr (assoc 'end err))))))
                     (overlay-put overlay 'face 'next-error)
                     overlay)) errors))
  (message "(pending error, use C-c C-x to jump)"))


        (highlight (merlin-update-highlight-lock-zone))))
   merlin-display-lock-zone))


(defun merlin-update-margin-lock-zone ()
  (if merlin-lock-zone-margin-overlay
      (delete-overlay merlin-lock-zone-margin-overlay))
