when I specify listKey="key"
than I get <option value="">Host</option>
when I remove listKey and specify listValue="value"
I get <option value="Host"></option>
when I specify both
I get <option value=""></option>
when I remove both listKey and listValue
I get <option value="Host">Host</option> plus all the others
but when I didn't have listKey and listValue specify, the headerValue="- Please Select -" is not displayed when I load the page