$('.left-menu > li').hover(function(event) {
    $('.left-menu > li').removeClass('hover');
    window.menuTimeoutHoverIn = setTimeout(function(){
        $(event.target.closest('.dropdown')).addClass('hover');
    }, 300);
}, function(event){
    window.menuTimeoutHoverOut = setTimeout(function(){
        $(event.target.closest('.dropdown')).removeClass('hover');
    }, 300);
});