I have WP 3.4.2 with Arras theme.
Today, I changed my main menu to another one on freewheely.com
The menus drop down correctly, but when the mouse goes away from the main menu to go to a submenu, this submenu disappears. You can try it now.
So I reverted to the former menu I had and worked fine. Now even this one do not work anymore. I have changed nothing in the meantime, except a new post.
Would anyone have a hint for solving this problem?