Hi we have a site with which on one page we have a modalpopup extender control to display a warnings panel when the application requires.  however after the first time the panel is displayed, which is displayed correctly in the center of the page, subsequent raisings of the popup panel are displayed at the head of the page as they flow in the html.  This is not the desired outcome, we'd like to popup to always display in the center of the page, regardless of whether it is the nth time of appearing or not.  Has anyone experienced this sort of behaviour?

<contenttemplate>
            <ajax:modalpopupextender repositionmode="RepositionOnWindowResizeAndScroll" backgroundcssclass="modalBackground" targetcontrolid="btnModalExtend" popupcontrolid="pnlWarnings" id="objModalExtender" runat="server">
            </ajax:modalpopupextender>
            <asp:panel id="pnlWarnings" runat="server" cssclass="WarningsPanel" style="z-index:100;">
                    <asp:label id="lblWarnings" runat="server">
                    </asp:label>
                    <asp:panel id="pnlWarningText" runat="server">
                        <asp:bulletedlist id="bltWarnings" runat="server">
                        </asp:bulletedlist>
                        <asp:panel id="pnlPressureWarnings" runat="server" visible="false">
                            <p>
                                <asp:label id="lblReduction1" runat="server">
                                </asp:label></p>
                            <p>
                                <asp:label id="lblReduction2" runat="server">
                                </asp:label></p>
                            <p>
                                <asp:linkbutton id="lnkReduction1" runat="server">
                                </asp:linkbutton></p>
                            <p>
                                <asp:linkbutton id="lnkReduction2" runat="server">
                                </asp:linkbutton></p>
                            <p>
                                <asp:linkbutton id="lnkReduction3" runat="server"></asp:linkbutton></p>
                        </asp:panel>
                    </asp:panel>
                    <asp:button id="btnOK" runat="server" text="Ok" causesvalidation="False" class="WarningsPanelButtons"></asp:button>
                    <asp:button id="btnCancel" runat="server" text="Cancel" causesvalidation="False" class="WarningsPanelButtons"></asp:button>
                </asp:panel>

Associated style:

.WarningsPanel
{
    background: white;
    border: solid 2px #333333;
    width: 600px;
    height: auto;
}
.WarningsPanel li
{
    list-style-type: none;
    margin-right: 2.5em;
}
.WarningsPanelButtons
{
    float:right;
    margin:0.5em;
}