@jan-welch: Hello there,
If you check the readme.txt file in the theme folder it is mentioned that If a large number of top level items are used in primary menu, there might be design issue. Please add only 6 menu items approximately.
If you upgrade to pro version of the theme there is an option to have horizontal menu layout using which you can fit more number of menu items but using the Vertical Menu layout it is not possible to have large number of menu items. You can check out other additional-features available in pro version of the theme.
Let me know if this helps you out!
Kind Regards,
Skandha