Docstring improvement

lisp/ChangeLog

@@ -1,3 +1,7 @@
+2009-06-14  Carsten Dominik  <carsten.dominik@gmail.com>
+
+	* org.el (org-open-non-existing-files): Improve docstring.
+
 2009-06-11  Carsten Dominik  <carsten.dominik@gmail.com>
 
 	* org-icalendar.el (org-icalendar-include-bbdb-anniversaries): New

lisp/org.el

@@ -1224,7 +1224,10 @@ changes to the current buffer."
 
 (defcustom org-open-non-existing-files nil
   "Non-nil means, `org-open-file' will open non-existing files.
-When nil, an error will be generated."
+When nil, an error will be generated.
+This variable applies only to external applications because they
+might choke on non-existing files.  If the link is to a file that
+will be openend in Emacs, the variable is ignored."
   :group 'org-link-follow
   :type 'boolean)