overflow not working in ul overflow-x scroll code example

Example: overflow not working in ul overflow-x scroll

ul {
    width: 300px;
    overflow-x: scroll;
    background: #ccc;
    white-space:nowrap;
    display:inline-block;
}

li {
    display: inline-block;
    
    /* if you need ie7 support */
    *display: inline;
    zoom: 1
}