Hi, volatilepuppy,
Throughout test, I find that “Div” can be rendered by both IE and Firefox. I think the problem may be caused by different versions(my Firefox vision 1.8.20070.30919) of the Firefox since my div can be rendered OK.
See the test code as follows:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="I20070430-2.aspx.cs" Inherits="_200704_I20070430_2" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>DivTest</title>
</head>
<body>
<form id="form1" runat="server">
<div style="height:300px; border: solid 1px red; z-index:100;" >
<div style="height:200px; border: solid 1px green; z-index:101;" >
<div style="height:100px; border: solid 1px black;" >
<div style="height:auto; border: solid 1px green;" >
</div>
</div>
</div>
</div>
<div style="height:auto; border: solid 1px red; z-index:103" >
<div style="height:auto; border: solid 1px green; z-index:102" >
</div>
</div>
</form>
</body>
</html>
Please check it. Waitting for your feeds back.
Hope it helps.