.extRef_combobox {
        border: solid 1px #000000;
}
.extRef_combobox INPUT {
        border: none;
        height: 20px;
        width: 400px;
}
.extRefPopup {
        background: #FFFFFF;
        border: solid 1px #000000;
        position: absolute; 
        display: none;
        overflow: auto;
        width: 420px; 
        height: 300px;
}
.extRefSelected {
        background: #3399ff;
        color: #FFFFFF;
}
.extRefUnSelected {
        background: #FFFFFF;
        color: #000000;
}