带有updatepanel的PopupControlExtender: chrome的问题

<asp:Panel ID="CreateGroupPanel" runat="server" 
           CssClass="style10" Visible="True" >
                <asp:ToolkitScriptManager ID="ToolkitScriptManager1" 
                                          runat="server">
                </asp:ToolkitScriptManager>
                <asp:UpdatePanel ID="UpdatePanel1" runat="server">
....
</ asp:UpdatePanel>
</asp: Panel>

<asp:Button ID="Btn_CreateGroupPopUp " 
            runat="server" 
            Text="Create Group" 
            Width="109px" />
<asp:PopupControlExtender ID="PopupControlExtender1" runat="server"
                          DynamicServicePath=""
                          Enabled="True" ExtenderControlID="" 
                          TargetControlID="Btn_CreateGroupPopUp" 
                          PopupControlID="CreateGroupPanel">
</asp:PopupControlExtender>
<asp:Panel ID="CreateGroupPanel" runat="server"