since the last update 1.7.1 the horizontal nav menu is displayed as li elements and not formated the correct way anymore on older browsers. Sure, users should keep their browsers updated, but this is not possible in all scenarios. It was working with 1.7.0.
However, the problem should also have occurred with 1.7, because the “originator” was introduced in 1.7. With 1.6.2 there should be no problems. We are currently working on a solution.