That’s because the main menu is designed to only contain one line of pages. You have two lines of pages.
One alternative is to use a custom menu, but tweak it a bit by adding some submenus. The other alternative is to restyle the main menu using a child theme or custom CSS. My tutorial on custom menus is here: http://blog.kjodle.net/2011/08/25/how-to-create-and-use-custom-menus-in-wordpress/
You can join us at the Graphene support forum, where there is lots of discussion about restyling the main menu (and everything else).
http://forum.khairul-syahir.com/
Thanks for including a link!
Thread Starter
Carma
(@carma)
Thanks for the info! I will shorten my menu for now and then look into your suggestions for restyling it.