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 (https://forum.websitebaker.org/index.php/topic,30768.msg214439.html#msg214439)), 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 navigations (https://forum.websitebaker.org/index.php/topic,23012.%20msg155271.%20html#msg155271)
and here ->
Show_Menu2 - README + Lösungen für verschiedene Menüs (https://forum.websitebaker.org/index.php/topic,23004.%20msg155212.%20html#msg155212)
as well as in many articles about show_menu2 ()
Admin edit: removed hint to use alternate functions, because produce a lot of error messages