diff --git a/gtk/gtkshow.c b/gtk/gtkshow.c
index b2b56918a2..642584bf41 100644
--- a/gtk/gtkshow.c
+++ b/gtk/gtkshow.c
@@ -37,8 +37,10 @@
  * @error: a #GError that is returned in case of errors
  *
  * This is a convenience function for launching the default application
- * to show the uri. The uri must be of a form understood by GIO. Typical
- * examples are
+ * to show the uri. The uri must be of a form understood by GIO (i.e. you
+ * need to install gvfs to get support for uri schemes such as http://
+ * or ftp://, as only local files are handled by GIO itself).
+ * Typical examples are
  * <simplelist>
  *   <member><filename>file:///home/gnome/pict.jpg</filename></member>
  *   <member><filename>http://www.gnome.org</filename></member>