Which theme are you using? TwentyEleven seems to so this, working on a fix… Try with TwentyTwelve or use the latest release candidate at http://www.wpsymposium.com the now shows a horizontal menu instead? Maybe continue your post at the WPS forums via the same site. Thank you 🙂
A further update, the latest release candidate (13.04 RC3) will soon be available, that should fix the position of the menu links as you’ve described and on your screenshot 🙂 Tested with TwentyEleven, for example.