Due to an accident while recoding the file "frontend.functions.
php" it was forgotten to add the old function show_menu ().
Since this function show_menu () has been deprecated for years (see also
here), we decided not to provide this function with a fix.
Help for changing over to the show_menu2 () function can be found here ->
Show_Menu2 - README + Solutions for different navigationsand here ->
Show_Menu2 - README + Lösungen für verschiedene Menüsas well as in many articles about show_menu2 ()
Admin edit: removed hint to use alternate functions, because produce a lot of error messages