Setting the css position attribute (ie. fixed, relative, etc. )on a panelPopup style in a Portlet has no effect and looks as if it's being hard coded as absolute. Here is the jspx code:

<ice:panelPopup style="position: fixed; z-index:999; top: 10px;left: 400px; width: 400px; height: 200px;background: #FFFFFF;" autoCenter="false" modal="true" rendered="#{backingBean.rendered}">

which renders out the following :

<div class="icePnlPop" ..... style="background: rgb(255, 255, 255) none repeat scroll 0% 0%; -moz-background-clip: -moz-initial; -moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial; z-index: 25001; top: 135.5px; left: 399px; width: 400px; height: 200px; visibility: visible; position: absolute;">

Notice the position:absolute set at the very end. Inspecting the css using Firebug yields the following curious styleclass:

element.style {
background-attachment:scroll;
background-color:#FFFFFF;
background-image:none;
background-position:0 0;
background-repeat:repeat;
height:200px;
left:399px;
position:absolute;
top:135.5px;
visibility:visible;
width:400px;
z-index:25001;
}

This is also happening with IE7.