Custom Menu V10
The Custom Menu Hook introduced in TNG V9 was re-written in TNG V10 to simplify how entries are coded by the user in the customconfig.php.
The Site Menu Mod as currently provided for TNG V9 is obsolete.
The Custom Drop Down Menu mod is now obsolete since it has been incorporated into TNG V10
See Converting Custom Menu Hook on how to convert your Site Menu Mod entries to use the new syntax.