JS error after closing window with GroupTabPanel

[Svr77]

Hello All,

I have small partitial view that contains window with GroupTabPanel. The window is showing fine, but every time when I close it it shows me JS-error in Firebug (see the picture).



Please see attached code:

Window.ascx

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<dynamic>" %>
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>

    <ext:Window 
            ID="Window2" 
            runat="server" 
            Title="Hello World!"  
            Icon="Application"
            Height="500px" 
            Width="800px"
            Layout="Border"
            CloseAction="Close">
            <Items>
              <ext:GroupTabPanel ID="Panel1" runat="server" TabWidth="130" ActiveGroupIndex="0" Region="Center" >
              <Groups>
                <ext:GroupTab ID="GroupTab1" runat="server">
                  <Items>
                    <ext:Panel ID="Panel2" runat="server" Title="Tickets" Layout="fit" Icon="TagBlue" TabTip="Tickets tabtip" />
                    <ext:Panel ID="Panel3" runat="server" Title="Subscriptions" Icon="Newspaper" TabTip="Subscriptions TabTip" Layout="Fit"/>
                    <ext:Panel ID="Panel5" runat="server" Title="Users" Icon="Group" TabTip="Users tabtip" />
                  </Items>
                </ext:GroupTab>
                <ext:GroupTab ID="GroupTab2" runat="server">
                  <Items>
                    <ext:Panel ID="Panel6" runat="server" Title="Configuration" TabTip="Configuration tabtip" />
                    <ext:Panel ID="Panel7" runat="server" Title="Email Templates" TabTip="Templates tabtip" Icon="Email" />
                  </Items>
                </ext:GroupTab>
              </Groups>
              </ext:GroupTabPanel>                
            </Items>
        </ext:Window>

Controller

        public ActionResult ShowWindow()
        {
            PartialViewResult pr = new PartialViewResult();
            pr.ViewName = "Window";
            pr.SingleControl = true;

            return pr;
        }

Main view

    <ext:ViewPort ID="ViewPort1" runat="server" Layout="border">
        <Items>
            <ext:Toolbar ID="Toolbar1" 
                runat="server" 
                Region="North" 
                Height="25" 
                Margins="0 0 4 0">
                <Items>
                    <ext:Button ID="Button6" runat="server" Text="Show Window">
                      <DirectEvents>
                        <Click Url="/Tender/ShowWindow" />
                      </DirectEvents>
                    </ext:Button>                            
                </Items>
            </ext:Toolbar>
            <ext:Panel id="Panel" runat="server" Region="Center" />                  
        </Items>
    </ext:ViewPort>

What is the resons of this error?

Regards,
Alexander

[Svr77]

Hello, Is there any update on this?