Line break / element.style width inserted

I am using Nice Menus with Zen Theme in Drupal 7.8. After adding a sub link (Züchter) to a main menu item (Zucht), the main menu item loses the last letter to the next line. When I click on the submenu, nice menu adds an element.style width="54px" to the code and causes the link text to break: i.e. the last letter of the link shows up in the next line. Why is the width added and how can I get rid of it?

Screenshot
http://foxterrierklub.einstern.at/de/züchter-0#