Does accordion have any issues with IE6/7. Accordion on my webpage initially opens up all the panes. But, it works fine in Firefox as expected. I have attached the code below. The webpage has a text box on it and once the user clicks on the Button, the content in the accordion panes is refreshed.

<%@ Page Language="VB" MasterPageFile="~/TestMaster.master" AutoEventWireup="false" CodeFile="poDetails.aspx.vb" Inherits="poDetails" title="Items Approval Page." %>

<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">

<script type="text/javascript">
            function toggleFade() {
                var behavior = $object('MyAccordion_AccordionProperties');
                if (behavior) {
                    behavior.set_FadeTransitions(!behavior.get_FadeTransitions());
                }
            }
            function changeAutoSize() {
                var behavior = $object('MyAccordion_AccordionProperties');
                var ctrl = $('autosize');
                if (behavior) {
                    var size = 'None';
                    switch (ctrl.selectedIndex) {
                        case 0 :
                            behavior.control.element.style.height = 'auto';
                            size = 'None';
                            break;
                        case 1 :
                            behavior.control.element.style.height = '400px';
                            size = 'Fill';
                            break;
                        case 2 :
                            behavior.control.element.style.height = '400px';
                            size = 'Limit';
                            break;
                    }
                    behavior.set_AutoSize(size);
                }
                if (document.focus) {
                    document.focus();
                }
            }
</script>

<atlas:ScriptManager ID=sm1 runat=server EnablePartialRendering=true />
<atlas:UpdateProgress ID=uprog1 runat=server>
    <ProgressTemplate>
        <img id="imgProg" runat="server" src="Images/indicator_mozilla_blu.gif" />
        <asp:Label id="lblProg" runat=server Text="Please wait..." Font-Names="Tahoma" Font-Size="8pt"></asp:Label>
    </ProgressTemplate>
</atlas:UpdateProgress>
<div>
<atlas:UpdatePanel ID=up1 runat=server Mode=always>
<ContentTemplate>
    <asp:TextBox ID="txtPO" runat=server Font-Names="Tahoma" Font-Size="8pt">
    </asp:TextBox>
    <atlasToolKit:FilteredTextBoxExtender ID="FilterTextBox" runat=server>
        <atlasToolKit:FilteredTextBoxProperties FilterType=Numbers TargetControlID="txtPO">
        </atlasToolKit:FilteredTextBoxProperties>
    </atlasToolKit:FilteredTextBoxExtender>
    <asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="Please enter a valid PO number" ControlToValidate="txtPO" Display="Dynamic" Font-Names="Tahoma" Font-Size="8pt">
    </asp:RequiredFieldValidator>
    <asp:Button ID="btnGo" runat=server Text="Go" Font-Names="Tahoma" Font-Size="8pt"/>
    <hr />
  
    <atlasToolkit:Accordion ID="MyAccordion" runat="server" SelectedIndex="0"
            HeaderCssClass="accordionHeader" ContentCssClass="accordionContent"
            FadeTransitions="false" FramesPerSecond="40" TransitionDuration="250" AutoSize="Limit">
           <Panes>
            <atlasToolkit:AccordionPane ID="poPane" runat=server >
                <Header><a href="" onclick="return false;" class="accordionLink">1. PO Information</a></Header>
                <Content>
                    <asp:DetailsView ID="dtlPO" runat=server AutoGenerateRows=false EmptyDataText="No PO selected." >
                        <Fields>
                            <asp:BoundField HeaderText="PO" DataField="po_no"/>
                            <asp:BoundField HeaderText="Vendor" DataField="vendor_name"/>
                            <asp:BoundField HeaderText="Rig" DataField="rig_no"/>
                            <asp:BoundField HeaderText="Contract" DataField="contract"/>
                            <asp:BoundField HeaderText="Requisition" DataField="req_no"/>
                            <asp:BoundField HeaderText="Currency" DataField="currency_code"/>
                            <asp:BoundField HeaderText="Approved" DataField="approval_status" />
                        </Fields>
                        <RowStyle BackColor="#EFF3FB" Font-Names="Tahoma" Font-Size="8pt" />
                        <EditRowStyle BackColor="#2461BF" Font-Names="Tahoma" Font-Size="8pt" ForeColor=White/>
                        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                        <HeaderStyle BackColor="#507CD1" Font-Bold="True" Font-Names="Tahoma" Font-Size="8pt"
                            ForeColor="White"/>
                        <AlternatingRowStyle BackColor="White" Font-Names="Tahoma" Font-Size="8pt" />                   
                    </asp:DetailsView>
                </Content>
            </atlasToolkit:AccordionPane>
            <atlasToolkit:AccordionPane ID="itemPane" runat=server>
                <Header><a href="" onclick="return false;" class="accordionLink">2. Items/Approvals</a></Header>
                <Content>
                    <asp:GridView ID="itemPO" runat=server EmptyDataText="No Items." AutoGenerateColumns=false>
                        <Columns>
                            <asp:BoundField HeaderText="Line" ItemStyle-HorizontalAlign=Left DataField="line_no" />
                            <asp:BoundField HeaderText="Part No" ItemStyle-HorizontalAlign=Left DataField="part_no" />
                            <asp:BoundField HeaderText="Description" ItemStyle-HorizontalAlign=Left DataField="description" />
                            <asp:BoundField HeaderText="Qty." ItemStyle-HorizontalAlign=Left DataField="qty_ordered" />
                            <asp:BoundField HeaderText="Cost" ItemStyle-HorizontalAlign=Right DataField="part_cost" />
                            <asp:BoundField HeaderText="Purchasing" ItemStyle-HorizontalAlign=Left DataField="po_dept_approved_on" />
                            <asp:BoundField HeaderText="Rig Manager" ItemStyle-HorizontalAlign=Left DataField="rigMgr" />
                            <asp:BoundField HeaderText="VP" ItemStyle-HorizontalAlign=Left DataField="vp" />
                            <asp:BoundField HeaderText="Executive" ItemStyle-HorizontalAlign=Left DataField="exec" />
                            <asp:BoundField HeaderText="Accounting" ItemStyle-HorizontalAlign=Left DataField="acctExec" />
                        </Columns>
                        <RowStyle BackColor="#EFF3FB" Font-Names="Tahoma" Font-Size="8pt" />
                        <EditRowStyle BackColor="#2461BF" Font-Names="Tahoma" Font-Size="8pt" ForeColor=White/>
                        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                        <HeaderStyle BackColor="#507CD1" Font-Bold="True" Font-Names="Tahoma" Font-Size="8pt"
                            ForeColor="White" />
                        <AlternatingRowStyle BackColor="White" Font-Names="Tahoma" Font-Size="8pt" />                                       
                    </asp:GridView>
                </Content>
            </atlasToolkit:AccordionPane>
            <atlasToolkit:AccordionPane ID="apPane" runat=Server>
                <Header><a href="" onclick="return false;" class="accordionLink">3. Payment Information</a></Header>
                <Content>
                    <asp:DetailsView ID="dtlAp" runat=server EmptyDataText="No Payments.">
                        <RowStyle BackColor="#EFF3FB" Font-Names="Tahoma" Font-Size="8pt" />
                        <EditRowStyle BackColor="#2461BF" Font-Names="Tahoma" Font-Size="8pt" ForeColor=White/>
                        <PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />
                        <HeaderStyle BackColor="#507CD1" Font-Bold="True" Font-Names="Tahoma" Font-Size="8pt"
                            ForeColor="White" />
                        <AlternatingRowStyle BackColor="White" Font-Names="Tahoma" Font-Size="8pt" />                                       
                    </asp:DetailsView>
                </Content>
            </atlasToolkit:AccordionPane>
           </Panes>
    </atlasToolkit:Accordion>
    </ContentTemplate>
    </atlas:UpdatePanel>        
</div>
</asp:Content>