Recently was manufacturing the HTML page, because many two row places needed one side to decide the width, another one side auto-adapted width. When needs under pulls the menu effect, regardless of the z-index value suppose to high, menu DIV throughout not in page most top layer.

HTML

<div class=”a”>
a <div class=”menu”>sub a</div>
</div>
<div class=”b”>
b
</div>

CSS

.a {
position:relative;
background:#f00;
}
.menu{
position:absolute;
background:#0ff;
height:50px;
z-index:99;
}
.b {
position:relative;
background:#ff0;
}

The above was the page code, menu z-index has supposed is 99, but in IE6, IE7 DIV[menu] throughout in div[b] under. Can only pass Canada to establish div[a] z-index the value to raise promotes the div[menu] stack-up altitude, but does not need in the red fox to establish. May see IE to be more orphaned than to the stack-up order succession the fire wants strict many. But myself think the fire orphaned way close designer’s intention. Although abhors IE and the red fox the CSS different analysis, also can only feel the helpless.