<atlas:UpdatePanel ID="UpdatePanelContact" runat="server">
        <ContentTemplate>
               <asp:GridView ID="OperationGrid" runat="server" AutoGenerateColumns="false">
                            <Columns>
                                <asp:TemplateField>
                                    <ItemTemplate>
                                        <asp:Panel CssClass="popupMenu" ID="PopupMenu" runat="server">
                                            <div style="border:1px outset white">
                                                 <asp:LinkButton ID="LinkButton1" runat="server" CommandName="Edit" Text="Edit"></asp:LinkButton> 
                                                <br />
                                                 <asp:LinkButton ID="LinkButton2" runat="server" CommandName="Delete" Text="Delete"></asp:LinkButton> 
                                            </div>
                                        </asp:Panel>

                                        <asp:Panel ID="Panel9" runat="server">
                                            <table width="100%">
                                                <tr>
                                                    <td width="25%"><asp:Label Font-Bold="true" ID="Label1" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "name") %>'></asp:Label></td>
                                                    <td width="25%"><asp:Label ID="Label2" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "creation_date") %>'></asp:Label></td>
                                                    <td width="25%"><asp:Label ID="Label3" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "last_modification_date") %>'></asp:Label></td>
                                                        
                                                </tr>
                                            </table>
                                        </asp:Panel>

                                        <atlasToolkit:HoverMenuExtender ID="hme2" runat="Server">
                                            <atlasToolkit:HoverMenuProperties HoverCssClass="popupHover" PopupControlID="PopupMenu" PopupPosition="Left" TargetControlID="Panel9" PopDelay="25"/>
                                        </atlasToolkit:HoverMenuExtender>
                                        
                                    </ItemTemplate>
                                </asp:TemplateField>   
                            </Columns>
                        </asp:GridView>
    </ContentTemplate>  
</atlas:UpdatePanel>

The extender needs to be created outside of the repeater so the scripts get properly loaded.  Try adding this to your page, outside the UpdatePanel

<atlasToolkit:HoverMenuExtender id="hme_script" runat="server" />

Hi

I've placed a HoverMenuExtender inside the grid, and its giving me javascript error at IE-6 that "Sys.Debug is null or not an object". At firefox its working fine. So could anyone help me out. Here is the code snippet

<radG:RadGrid ID="grdPhone" runat="server"

  AutoGenerateColumns="false"

  AllowAutomaticInserts="true"

  AllowAutomaticDeletes="true"

  AllowAutomaticUpdates="true"

  AllowMultiRowSelection="true"

  AllowPaging="false"

  EnableAJAX="true"

  EnableAJAXLoadingTemplate="true"

  EnableOutsideScripts="true"

  ShowHeader="true">

    <MasterTableView DataKeyNames="ID">

      <Columns>

        <radG:GridTemplateColumn HeaderText="Main" DataField="IsPhone">

          <ItemTemplate>

            <asp:Panel ID="Panel1" runat="server">

              <asp:CheckBox ID="chkMain" runat="server" Checked='<%# Eval("IsPhone") %>' Enabled="false"/>

              </asp:Panel>

            <cc1:HoverMenuExtender ID="HoverMenuExtender1" runat="server" TargetControlID="Panel1"

             PopupControlID="PopupMenu" PopupPosition="Left" PopDelay="50" />

            <asp:Panel ID="PopupMenu" runat="server">

              <div style="border:1px outset white">

                <asp:LinkButton ID="LinkButton1" runat="server" CommandName="Edit" Text="Edit" />

                <br />

                <asp:LinkButton ID="LinkButton2" runat="server" CommandName="Delete" Text="Delete" />

                </div>

            </asp:Panel>

          </ItemTemplate>

        </radG:GridTemplateColumn>

      </Columns>

      </MasterTableView>

        <ClientSettings>

          <Selecting AllowRowSelect="true"  />

          <ClientEvents OnRowMouseOver="RowMouseOver" />

        </ClientSettings>

    </radG:RadGrid>