This was from a forum post a while ago.
I cant find the thread or author so....
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<title>Error with Select tags</title>
<script language="JavaScript1.2">
<!-- Script Begin
function Toggle(e) {
if (document.all["testit"].style.visibility == "visible"

{
document.all["testit"].style.visibility = "hidden";
document.all["testdiv"].style.visibility = "visible";
e.value = "Click to Show layer";
}else{
document.all["testit"].style.visibility = "visible";
document.all["testdiv"].style.visibility = "hidden";
e.value = "Click to Hide layer";
}}
// Script End -->
</script>
</head>
<body>
<div id="testit" name="TestIT" style="position: absolute; top: 80; left: 20; visibility: hidden; z-index: 1000; height: 300px; width: 400px; background: #0066CC; font-family: sans-serif; font-size: medium; color: #FFFFFF">Is is not possible for me to get this layer on top of select tags<br>does anyone know about this problem ??<br>It's mayme IE ??</div>
<input type="button" name="ChangeLayer" onclick="Toggle(this);" value="Click to Show layer">
<br><br><br>
test Area<br>
<div id="testdiv" style="visibility: visible;">
<input type="text" size="50" value="This is only a input tag there will be hidden under the displayed layer"><br>
<input type="radio" size="50">This is only a input tag there will be hidden under the displayed layer<br>
<input type="checkbox" size="50">This is only a input tag there will be hidden under the displayed layer<br>
<input type="button" size="50" value="This is only a input tag there will be hidden under the displayed layer" ><br>
<br>This will underneath layer when it's displayed<br>
<select name="test">
<option>Its not possible to hide this under the displayed layer</option>
<option>To my knowledge, a select tag ignores z-index'es</option>
</select><br><br>
<select name="test" style="z-index:2" multiple size="4">
<option>Its not possible to hide this under the displayed layer even it is indexed</option>
<option>To my knowledge, a select tag ignores z-index'es</option>
</select>
</div>
</body>
</html>