GUI Windows Form C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
public class Form1 : Form
{
    private System.Windows.Forms.Label lblCount;
    List squares = new List();
  public Form1() {
        InitializeComponent();
        
  }
    private void NonOptimizedSquares_Paint(object sender, PaintEventArgs e)
    {
      Pen pen = new Pen(Color.Red, 10);
      foreach (Rectangle square in squares) {
        e.Graphics.DrawRectangle(pen, square);
      }
      pen.Dispose();
      lblCount.Text = " " + squares.Count.ToString() + " squares"; 
    }
    private void NonOptimizedSquares_MouseDown(object sender, MouseEventArgs e)
    {
      if (e.Button == MouseButtons.Left)
      {
        Rectangle square = new Rectangle(e.X, e.Y, 20, 20);
        squares.Add(square);
                square.Inflate(1, 1);
                Invalidate(square);
      } 
    }
    private void InitializeComponent()
    {
      this.lblCount = new System.Windows.Forms.Label();
      this.SuspendLayout();
      // 
      // lblCount
      // 
      this.lblCount.BorderStyle = System.Windows.Forms.BorderStyle.Fixed3D;
      this.lblCount.Dock = System.Windows.Forms.DockStyle.Bottom;
      this.lblCount.Location = new System.Drawing.Point(0, 251);
      this.lblCount.Name = "lblCount";
      this.lblCount.Padding = new System.Windows.Forms.Padding(2);
      this.lblCount.Size = new System.Drawing.Size(299, 21);
      this.lblCount.TabIndex = 0;
      // 
      // NonOptimizedSquares
      // 
      this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
      this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
      this.ClientSize = new System.Drawing.Size(299, 272);
      this.Controls.Add(this.lblCount);
      this.Font = new System.Drawing.Font("Tahoma", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
      this.Name = "NonOptimizedSquares";
      this.Text = "NonOptimizedSquares";
      this.Paint += new System.Windows.Forms.PaintEventHandler(this.NonOptimizedSquares_Paint);
      this.MouseDown += new System.Windows.Forms.MouseEventHandler(this.NonOptimizedSquares_MouseDown);
      this.ResumeLayout(false);
    }
  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }
}