.ui-autocomplete {
    max-height: 100px;
    overflow-y: auto;
    /* prevent horizontal scrollbar */
    overflow-x: hidden;
    /* add padding to account for vertical scrollbar */
    padding-right: 20px;
    font-size: 12px;
  padding-bottom: 2px;
}
/* IE 6 doesn't support max-height
 * we use height instead, but this forces the menu to always be this tall
 */
* html .ui-autocomplete {
    height: 100px;
}