Index: sbbs.el
==================================================================
--- sbbs.el
+++ sbbs.el
@@ -600,11 +600,11 @@
           (goto-char end)
           (insert style)
           (goto-char beg)
           (insert style))
       (insert style style)))
-  (when (< (point) (mark))
+  (when (or (not (mark)) (< (point) (mark)))
     (forward-char (length style))))
 
 (defun sbbs-compose-format-code ()
   "Insert code syntax markers."
   (interactive)