Modal Popup Always Visible

DialogRestoreEventArgs.cs
----------------------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
    public class DialogRestoreEventArgs
    {
        Dictionary<string, string> _paramValues = null;
        public DialogRestoreEventArgs()
        {
            _paramValues = new Dictionary<string, string>();
        }
        public Dictionary<string, string> ArgumentValues
        {
            get
            {
                return _paramValues;
            }
            set
            {
                _paramValues = value;
            }
        }
        public void AddParam(string key, string value)
        {
            if (_paramValues == null)
                _paramValues = new Dictionary<string, string>();
            if (_paramValues.ContainsKey(key))
                throw new DuplicateNameException(string.Format("Parameter {0} already exist in argument collection", key));
            _paramValues.Add(key, value);
        }
        public string GetParam(string key)
        {
            if (_paramValues == null)
                return string.Empty;
            if (!_paramValues.ContainsKey(key))
                throw new ArgumentException(string.Format("Parameter key {0} not found in collection", key));
            return _paramValues[key];
        }
    }

Email.ascx
--------------
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="Email.ascx.cs" Inherits="MyCollections.UserControls_Email" %>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
Email.ascx.cs
-----------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace MyCollections
{
    public partial class UserControls_Email : System.Web.UI.UserControl
    {
        public delegate void DialogRestoreEventHandler(object senders, DialogRestoreEventArgs e);
        public event DialogRestoreEventHandler RestoreModalDialog;
        
        protected void Button1_Click(object sender, EventArgs e)
        {
            if (RestoreModalDialog != null)
            {
                DialogRestoreEventArgs evnts = new DialogRestoreEventArgs();
                RestoreModalDialog(sender, evnts);
            }
        }
    }
}

Default.aspx
--------------
<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
    CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Register Src="~/UserControls/Email.ascx" TagName="CustomerEmail" TagPrefix="CustEmail" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="asp" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
 
    
    <asp:Button ID="btn1" runat="server" Text="Submit" />
    <div id="myMailDiv" style="width: 50%; height: 50%;">
    <asp:Button runat="server" ID="btnSendMail" Style="display: none" />
    <asp:ModalPopupExtender ID="ModelpopEmail" runat="server" TargetControlID="btn1"
        PopupControlID="panelSendEmail" BackgroundCssClass="modalBackground">
    </asp:ModalPopupExtender>
    <asp:Panel ID="panelSendEmail" runat="server" BackColor="white" BorderColor="Black">
        <div id="emailDiv" style="border: 1px solid #666666; padding: 5px;">
            <div id="customerinfogrid" style="width: 97%;">
                <div id="gridimg">
                  <%--  <img src="Images/emailthisproperty.png">--%>
                </div>
                <div id="gridtxt">
                    Customer Email
                </div>
            </div>
           <%-- <asp:Button ID="Button1" runat="server" Text="Cancel" OnClick="btncancel_Click" />--%>
            <div>
                <asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
                <CustEmail:CustomerEmail ID="CustomerEmail1" runat="server" />
                
          
            </div>
           <asp:Button ID="btncancel" runat="server" Text="Cancel" OnClick="btncancel_Click" />
            <asp:Button ID="btnOpen" runat="server" Text="Open" OnClick="btnOpen_Click" />
        </div>
          
    </asp:Panel>
</div>
</asp:Content>

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using MyCollections;
public partial class _Default : System.Web.UI.Page
{
   
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        
        CustomerEmail1.RestoreModalDialog += new UserControls_Email.DialogRestoreEventHandler(CustomerEmail1_RestoreModalDialog);
    }
    void CustomerEmail1_RestoreModalDialog(object senders, DialogRestoreEventArgs e)
    {
        ModelpopEmail.Show();
    }
    
    protected void Button_Click(object sender, EventArgs e)
    {
        ModelpopEmail.Show();
    }
    protected  void Page_Load(object sender,EventArgs e)
    {
      //  base.OnInit(e);
      //  btn1.Click += new EventHandler(btnShowText_Click);
    }
    
    void btnShowText_Click(object senders, EventArgs e)
    {
      //  ModelpopEmail.Show();
    }
    protected void btncancel_Click(object senders, EventArgs e)
    {
        ModelpopEmail.Hide();
    }
    //btnOpen_Click
    protected void btnOpen_Click(object senders, EventArgs e)
    {
        ModelpopEmail.Show();
    }
    static void Button1_Click(object o, EventArgs e)
    {
            //Console.WriteLine("Event being called.");
            //Console.ReadLine();
    }
    protected static void OnMyTestEvent(object sender, EventArgs e)
    {
        
    }
}