[jQuery] conflict in list menu: overlapping lists

[pepijn]

i use this function to show/hide the second level.
But when i use the slideDown method the sublevel menu sometimes is
still visible during hovering another list item with classname niv1,
so you get 2 levels overlapping and i don't want that of course. It is
a crossbrowser problem. Is anyone familiar with this problem?

function Menu(){

                $('li.niv1').hover(
                        function(){
                           var elm = $(this).find("ul.submenu");
                        elm.slideDown('fast');
                        },
                        function(){
                          var elm = $(this).find("ul.submenu");
                        elm.hide();
                        });

}