[syslinux] bug report : menu.c32

[anctop]

This is to report a bug with "menu.c32".

I've found that this module does not behave correctly if the last menu
item is disabled.

syslinux.cfg
========================================
DEFAULT X1
UI menu.c32
#
LABEL X1
  MENU LABEL First item
  COM32 hdt.c32
#
LABEL X2
  MENU LABEL Second item
  MENU DISABLE
========================================

The last item is disabled , but the selection bar can still get into it.