Default
Menu is set to Horizontal (across),If you want this menu to be vertical
(Up/Down) please check this checkbox. Note:
If you check this box. Your Site will use a new template called "The main
template-Vertical" That you need to edit in the | Site
Templates | option in the main menu. It is best to use the same html
you used for the "The main template" to keep the site looking the same if you
ever switch back