The arrows in the dropdown meny pointing upp instead of down!?

Something has happened with my meny. The dropdown list has changed so the arrows points up instead of down!? That means that the under categories of one category shows above the main categories. Then you can´t see all the under categories of one side, because they are hidden under the top of the site. I don´t know then this happened, maybe then the theme was upgrade to the newest version. A bug? Somebody who has the same problem? And what should I do?!