using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form  
    {
        Form2 a;
        
        public Form1()
        {
            
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            // Display color dialog
            colorDialog1.ShowDialog();
            //Set the form's background color
            this.BackColor = colorDialog1.Color;
        }
        private void button2_Click(object sender, EventArgs e)
        {
            //Form2 myForm2 = new Form2();

            //myForm2.Show();
            if (a == null)
            {
                a = new Form2();
                a.Show();
            }
            else
            {
                 
            }
              
            
        }
    }
}

static bool opened = false;

private void Form2_Load(object sender, EventArgs e)
{
if (!opened)
   opened = true;
else
   this.Dispose();
}