header, .navbar {
    position: relative;
    z-index: 9999 !important;
}
.dropdown-menu {
    position: absolute !important;
    z-index: 10000 !important;
}
.dropdown-submenu {
    position: relative;
}
.dropdown-submenu .dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -1px;
    margin-left: 0;
}
.container-fluid, .row {
    overflow: visible !important;
}