Den ene ListBox overlapper den anden

højreklik på den der er filled og tryk brig to front:
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using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace WindowsApplication1
{
    /// <summary>
    /// Summary description for Form1.
    /// </summary>
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.ListBox listBoxfill;
        private System.Windows.Forms.ListBox listBoxleft;
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.Container components = null;

        public Form1()
        {
            //
            // Required for Windows Form Designer support
            //
            InitializeComponent();

            //
            // TODO: Add any constructor code after InitializeComponent call
            //
        }

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose( bool disposing )
        {
            if( disposing )
            {
                if (components != null)
                {
                    components.Dispose();
                }
            }
            base.Dispose( disposing );
        }

        #region Windows Form Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.listBoxfill = new System.Windows.Forms.ListBox();
            this.listBoxleft = new System.Windows.Forms.ListBox();
            this.SuspendLayout();
            //
            // listBoxfill
            //
            this.listBoxfill.Dock = System.Windows.Forms.DockStyle.Fill;
            this.listBoxfill.Location = new System.Drawing.Point(120, 0);
            this.listBoxfill.Name = "listBoxfill";
            this.listBoxfill.Size = new System.Drawing.Size(600, 446);
            this.listBoxfill.TabIndex = 0;
            //
            // listBoxleft
            //
            this.listBoxleft.Dock = System.Windows.Forms.DockStyle.Left;
            this.listBoxleft.Location = new System.Drawing.Point(0, 0);
            this.listBoxleft.Name = "listBoxleft";
            this.listBoxleft.Size = new System.Drawing.Size(120, 446);
            this.listBoxleft.TabIndex = 1;
            this.listBoxleft.SelectedIndexChanged += new System.EventHandler(this.listBox2_SelectedIndexChanged);
            //
            // Form1
            //
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(720, 446);
            this.Controls.Add(this.listBoxfill);
            this.Controls.Add(this.listBoxleft);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);

        }
        #endregion

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.Run(new Form1());
        }

        private void listBox2_SelectedIndexChanged(object sender, System.EventArgs e)
        {
       
        }
    }
}