hi
below is my aspx page
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ChartofAccounts.aspx.cs" Inherits="Infinity.UI.Master.ChartofAccounts" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>Chart of Accounts</title>
        <link rel="stylesheet" type="text/css" href="../../cssInfin/cssInfin.css" media="screen" /> 
        <!--[if lt IE 9]>
            <script src="../../jsScript/html5.js"></script>
        <![endif]-->
        <script src="../../jsScript/jsInfin.js"></script>
        <script>

            function checkparent(obj) {

            }
        </script>
        <style type="text/css">.auto-style3 { width: 100px; }
        </style>
    </head>
    <body>
        <form id="form1" runat="server">
            <ext:ResourceManager ID="ResourceManager1" runat="server" />
        
            <ext:Window 
                ID="formWindow" 
                runat="server" 
                Height="500" 
                Title="Customer Master" 
                ShowOnLoad="true" 
                CenterOnLoad="true"
                Resizable="true"
                Closable="false"
                MinWidth="800"
                Width="800" 
                Layout="Fit"
                Padding="6"
                Maximized="true">
                <Items>  <ext:Label ID="Label1" runat="server" Text=""></ext:Label></Items>
                <Content> 
                    <ajaxToolkit:ToolkitScriptManager runat="server" ID="scriptmgm1">
                        <Scripts>
                            <%--To learn more about bundling scripts in ScriptManager see http://go.microsoft.com/fwlink/?LinkID=272931&clcid=0x409 --%>
                            <%--Framework Scripts--%>                
                            <asp:ScriptReference Name="jquery" />
                            <asp:ScriptReference Name="jquery.ui.combined" />
                            <asp:ScriptReference Name="WebForms.js"  Path="~/Scripts/WebForms/WebForms.js" />
                            <asp:ScriptReference Name="WebUIValidation.js"  Path="~/Scripts/WebForms/WebUIValidation.js" />
                            <asp:ScriptReference Name="MenuStandards.js" Path="~/Scripts/WebForms/MenuStandards.js" />
                            <asp:ScriptReference Name="GridView.js" Path="~/Scripts/WebForms/GridView.js" />
                            <asp:ScriptReference Name="DetailsView.js"  Path="~/Scripts/WebForms/DetailsView.js" />
                            <asp:ScriptReference Name="TreeView.js"  Path="~/Scripts/WebForms/TreeView.js" />
                            <asp:ScriptReference Name="WebParts.js"  Path="~/Scripts/WebForms/WebParts.js" />
                            <asp:ScriptReference Name="Focus.js"  Path="~/Scripts/WebForms/Focus.js" />
                            <asp:ScriptReference Name="WebFormsBundle" />
                            <%--Site Scripts--%>
                        </Scripts>
                    </ajaxToolkit:ToolkitScriptManager> 
                    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
                        <ContentTemplate>
                            <table style="width: 98%">
                                <tr>
                                    <td>
                                        <ext:ButtonGroup ID="ButtonGroup1" runat="server">
                                            <Items>
                                                <ext:TableLayout ID="TableLayout1" runat="server" Columns="4">
                                                    <Cells>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnAdd" runat="server" Flat="True" Text="New" Icon="Add" Cls="btnalign" StyleSpec="float:left; " >
                                                                <DirectEvents>
                                                <Click OnEvent="btnNewUser_Click" >
                                                    <EventMask ShowMask="true" Msg="Verifying..." MinDelay="1000" />
                                                </Click>
                                            </DirectEvents>
                                                            </ext:Button>
                                                        </ext:Cell>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnEdit" runat="server" Flat="True" Text="Edit" Icon="ApplicationEdit" Cls="btnalign" StyleSpec="float:left; " />
                                                        </ext:Cell>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnInActive" Flat="True" runat="server" Text="InActive" Icon="Decline" Cls="btnalign" StyleSpec="float:left; "/>
                                                        </ext:Cell>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnDelete" Flat="True" runat="server" Text="Delete" Icon="Delete" Cls="btnalign" StyleSpec="float:left; " />
                                                        </ext:Cell>
                                                    </Cells>
                                                </ext:TableLayout>
                                            </Items>
                                        </ext:ButtonGroup>
                                        
                                    </td>
                                    <td style="width: 30%;">
                                        <ext:ButtonGroup ID="ButtonGroup2" runat="server">
                                            <Items>
                                                <ext:TableLayout ID="TableLayout2" runat="server" Columns="2">
                                                    <Cells>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnCancel" Flat="True" runat="server" Text="Cancel" Icon="Cancel" Cls="btnalign" StyleSpec="float:left; " />
                                                        </ext:Cell>
                                                        <ext:Cell>
                                                            <ext:Button ID="btnSave" Flat="True" runat="server" Text="Save" Icon="DatabaseSave" Cls="btnalign" StyleSpec="float:left; " />
                                                        </ext:Cell>
                                                    </Cells>
                                                </ext:TableLayout>
                                            </Items>
                                        </ext:ButtonGroup>
                                    </td>
                                    <td style="width: 20%">
                                        <asp:Panel ID="Panel_Search" DefaultButton="btnSearch" runat="server" >
                                            <table style="width: 100%">
                                                <tr>
                                                    <td style="width: 70%">
                                                        <asp:TextBox ID="txtSearch" runat="server" CssClass="txtsearchsmall"></asp:TextBox>
                                                    </td>
                                                    <td>
                                                        <%--<asp:Button ID="btnSearch" runat="server" Text="Search" CssClass="btn"  TabIndex="2" />--%>
                                                        <ext:Button ID="btnSearch" Flat="True" runat="server" Text="Search" Icon="Find" Cls="btnalign" StyleSpec="float:left; " />
                                                    </td>
                                                </tr>
                                            </table>
                                        </asp:Panel>
                                    </td>
                                </tr>
                            </table>
                            <fieldset >
                                <legend>Chart Of Accounts
                                </legend>
                                <div style="height: 450px; margin-left: auto; margin-right: auto; overflow: auto; width: 100%;">
                                    <section style="background-color: white; float: left; height: 450px; overflow: auto; width: 40%;">
                                        <asp:TreeView ID="trvChartOfAccounts" runat="server" BackColor="White" Height="450px" Width="100%" ShowLines="True" CssClass="trvChartOfAccounts" OnSelectedNodeChanged="trvChartOfAccounts_OnSelectedNodeChanged">
                                        </asp:TreeView>
                                    </section>
                                    <section style="float: left; height: 100%; width: 60%;">
                                        <asp:Panel runat="server" ID="PanelAddnew">
                                            <div id="NewCoaDiv">
                                                <table style="width: 88%;">
                                                    <tr>
                                                        <td class="auto-style3">
                                                            <asp:Label ID="lblAccountName" runat="server" Text="Account Name"></asp:Label>
                                                        </td>
                                                        <td colspan="3">
                                                            <asp:TextBox ID="txtAccountName" runat="server" CssClass="text-XXbig" Width="300" MaxLength="50"></asp:TextBox>
                                                        </td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                    <tr>
                                                        <td class="auto-style3">&nbsp;</td>
                                                        <td>
                                                            <asp:CheckBox ID="chkMainGroup" runat="server" BorderColor="#99CCFF" Text="Is MainGroup?" AutoPostBack="True" />
                                                        </td>
                                                        <td>
                                                            <asp:CheckBox ID="chkallowSubAc" runat="server" AutoPostBack="True" BorderColor="#99CCFF"  Text="Allow Sub A/C?" />
                                                        </td>
                                                        <td>&nbsp;</td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                    <tr>
                                                        <td class="auto-style3">
                                                            <asp:Label ID="lblParentGroup" runat="server" Text="Parent Group"></asp:Label>
                                                        </td>
                                                        <td>
                                                            <asp:DropDownList ID="ddlParentGroup" runat="server" CssClass="text-medium" Width="150">
                                                            </asp:DropDownList>
                                                        </td>
                                                        <td>&nbsp;</td>
                                                        <td>&nbsp;</td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                    <tr>
                                                        <td class="auto-style3">
                                                            <asp:Label ID="lblParentGroup0" runat="server" Text="Type"></asp:Label>
                                                        </td>
                                                        <td>
                                                            <asp:DropDownList ID="ddlType" runat="server" CssClass="text-medium">
                                                            </asp:DropDownList>
                                                        </td>
                                                        <td>
                                                            <asp:Label ID="lblParentGroup1" runat="server" Text="ClassificationType"></asp:Label>
                                                        </td>
                                                        <td>
                                                            <asp:DropDownList ID="ddlClassificationType" runat="server" CssClass="text-medium">
                                                            </asp:DropDownList>
                                                        </td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                    <tr>
                                                        <td class="auto-style3">
                                                            <asp:Label ID="lblBalance" runat="server" Text="Balance"></asp:Label>
                                                        </td>
                                                        <td>
                                                            <asp:TextBox ID="txtBalance" runat="server" CssClass="text-small" MaxLength="12" Width="80" onblur="Dec2maskzero(this)" onkeypress="return isNumeric(event);"></asp:TextBox>
                                                            <asp:DropDownList ID="ddldr_cr" runat="server" CssClass="text-Xsmall">
                                                                <asp:ListItem>Dr</asp:ListItem>
                                                                <asp:ListItem>Cr</asp:ListItem>
                                                            </asp:DropDownList>
                                                        </td>
                                                        <td style="text-align: right;">
                                                            <asp:Label ID="lblAsofDate" runat="server" Text="As Of Date"></asp:Label>
                                                        </td>
                                                        <td>
                                                            <asp:TextBox ID="txtAsofDate" runat="server" CssClass="text-small" Width="80"></asp:TextBox>
                                                            <asp:MaskedEditExtender ID="txtAsofDate_MaskedEditExtender" runat="server" AcceptNegative="Left" Century="2000" CultureAMPMPlaceholder="" CultureCurrencySymbolPlaceholder="" CultureDateFormat="" CultureDatePlaceholder="" CultureDecimalPlaceholder="" CultureThousandsPlaceholder="" CultureTimePlaceholder="" DisplayMoney="Left" Enabled="True" ErrorTooltipEnabled="True" Mask="99/99/9999" MaskType="Date" TargetControlID="txtAsofDate">
                                                            </asp:MaskedEditExtender>
                                                            <asp:CalendarExtender ID="txtAsofDate_CalendarExtender" runat="server" Enabled="True" Format="dd/MM/yyyy" PopupButtonID="ImgFollowupdate" TargetControlID="txtAsofDate">
                                                            </asp:CalendarExtender>
                                                        </td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                    <tr>
                                                        <td class="auto-style3">
                                                            <asp:Label ID="lblRemarks" runat="server" Text="Remarks" ></asp:Label>
                                                        </td>
                                                        <td colspan="3">
                                                            <asp:TextBox ID="txtRemarks" runat="server" CssClass="text-XXbig" TextMode="MultiLine" Width="200" MaxLength="300"></asp:TextBox>
                                                        </td>
                                                        <td>&nbsp;</td>
                                                    </tr>
                                                </table>
                                            </div>
                                        </asp:Panel>
                                    </section>
                                </div>
                            </fieldset> 
                        </ContentTemplate>
                    </asp:UpdatePanel>
                </Content>
            </ext:Window>
        </form>
    </body>
</html>
below is my cs file
protected void btnNewUser_Click(object sender, EventArgs e)
        {
            //ExtNet.MessageBox.Show(new MessageBoxConfig
            //{
            //    Message = "button click event ",
            //    ProgressText = "Checking...",
            //    Width = 300
            //}
            //            );
            EnableControls();
            txtAccountName.Focus();
            
        }

        private void EnableControls()
        {
            txtAccountName.Enabled = true;
            chkMainGroup.Enabled = true;
            chkallowSubAc.Enabled = true;
            ddlParentGroup.Enabled = true;
            ddlClassificationType.Enabled = true;
            ddlType.Enabled = true;
            txtBalance.Enabled = true;
            ddldr_cr.Enabled = true;
            txtAsofDate.Enabled = true;
            txtRemarks.Enabled = true;
        }
but its not enable any control in the page but in debug this code executing..