I am having one editable grid. its having two columns, Column one edit type is combo box and another is text box.
After editing column 1 i click column 2 for editing, here focus is coming to column 2 and suddenly the focus is went out.

how to fix this?

Sample code
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="TestApp2010.Test.WebForm1" %>

<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <ext:ResourceManager ID="ResourceManager1" runat="server" />
    <div>
        <ext:GridPanel ID="GridPanel1" runat="server" Width="300" Height="200" Title="EditableGrid Plugin">
            <Store>
                <ext:Store ID="Store1" runat="server">
                    <Reader>
                        <ext:JsonReader>
                            <Fields>
                                <ext:RecordField Name="Value" Type="Int" />
                                <ext:RecordField Name="Text" Type="String" />
                            </Fields>
                        </ext:JsonReader>
                    </Reader>
                </ext:Store>
            </Store>
            <Plugins>
                <ext:EditableGrid ID="EditableGrid1" runat="server" />
            </Plugins>
            <ColumnModel>
                <Columns>
                    <ext:RowNumbererColumn />
                    <ext:Column Header="Value" DataIndex="Value" Width="130" Sortable="true">
                        <Editor>
                            <ext:ComboBox ID="cmb1" runat="server" TriggerAction="All">
                                <Items>
                                    <ext:ListItem Text="1" Value="1" />
                                    <ext:ListItem Text="2" Value="2" />
                                </Items>
                            </ext:ComboBox>
                        </Editor>
                    </ext:Column>
                    <ext:Column Header="Text" DataIndex="Text" Width="130" Sortable="true">
                        <Editor>
                            <ext:TextField ID="TextField1" runat="server" AllowBlank="false" />
                        </Editor>
                    </ext:Column>
                </Columns>
            </ColumnModel>
             <SelectionModel>
                <ext:RowSelectionModel ID="RowSelectionModel2" runat="server"  SingleSelect="true"/>
            </SelectionModel>
        </ext:GridPanel>
    </div>
    </form>
</body>
</html>
Code Behind
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using Ext.Net;

namespace TestApp2010.Test
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!X.IsAjaxRequest)
            {
                this.GridPanel1.Store.Primary.DataSource = new List<object>
            {
                new { 
                    Value = 1, 
                    Text = "One"
                },
                new { 
                    Value = 2, 
                    Text = "Two"
                },
                new { 
                    Value = 3, 
                    Text = "Three"
                },
                new { 
                    Value = 4, 
                    Text = "Four"
                },
                new { 
                    Value = 5, 
                    Text = "Five"
                }
            };

                this.GridPanel1.Store.Primary.DataBind();
            }
        }
    }
}