Try this... Run the form. Check a few items in the CheckedListBox. Go to Tab
2 and then back to Tab 1. Uh... what happened? The check marks are
cleared?!!

Any ideas???

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;

namespace TestCheck
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class Form1 : System.Windows.Forms.Form
{
 private System.Windows.Forms.TabControl tabControl1;
 private System.Windows.Forms.TabPage tabPage1;
 private System.Windows.Forms.TabPage tabPage2;
 private System.Windows.Forms.CheckedListBox checkedListBox1;
 private System.Windows.Forms.Label label1;
 /// <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.tabControl1 = new System.Windows.Forms.TabControl();
  this.tabPage1 = new System.Windows.Forms.TabPage();
  this.tabPage2 = new System.Windows.Forms.TabPage();
  this.checkedListBox1 = new System.Windows.Forms.CheckedListBox();
  this.label1 = new System.Windows.Forms.Label();
  this.tabControl1.SuspendLayout();
  this.tabPage1.SuspendLayout();
  this.tabPage2.SuspendLayout();
  this.SuspendLayout();
  //
  // tabControl1
  //
  this.tabControl1.Controls.Add(this.tabPage1);
  this.tabControl1.Controls.Add(this.tabPage2);
  this.tabControl1.Location = new System.Drawing.Point(16, 16);
  this.tabControl1.Name = "tabControl1";
  this.tabControl1.SelectedIndex = 0;
  this.tabControl1.Size = new System.Drawing.Size(680, 432);
  this.tabControl1.TabIndex = 0;
  //
  // tabPage1
  //
  this.tabPage1.Controls.Add(this.checkedListBox1);
  this.tabPage1.Location = new System.Drawing.Point(4, 25);
  this.tabPage1.Name = "tabPage1";
  this.tabPage1.Size = new System.Drawing.Size(672, 403);
  this.tabPage1.TabIndex = 0;
  this.tabPage1.Text = "tabPage1";
  //
  // tabPage2
  //
  this.tabPage2.Controls.Add(this.label1);
  this.tabPage2.Location = new System.Drawing.Point(4, 25);
  this.tabPage2.Name = "tabPage2";
  this.tabPage2.Size = new System.Drawing.Size(672, 403);
  this.tabPage2.TabIndex = 1;
  this.tabPage2.Text = "tabPage2";
  //
  // checkedListBox1
  //
  this.checkedListBox1.Location = new System.Drawing.Point(24, 24);
  this.checkedListBox1.Name = "checkedListBox1";
  this.checkedListBox1.Size = new System.Drawing.Size(624, 344);
  this.checkedListBox1.TabIndex = 0;
  //
  // label1
  //
  this.label1.Location = new System.Drawing.Point(248, 168);
  this.label1.Name = "label1";
  this.label1.TabIndex = 0;
  this.label1.Text = "Nothing Here";
  //
  // Form1
  //
  this.AutoScaleBaseSize = new System.Drawing.Size(6, 15);
  this.ClientSize = new System.Drawing.Size(712, 464);
  this.Controls.Add(this.tabControl1);
  this.Name = "Form1";
  this.Text = "Form1";
  this.Load += new System.EventHandler(this.Form1_Load);
  this.tabControl1.ResumeLayout(false);
  this.tabPage1.ResumeLayout(false);
  this.tabPage2.ResumeLayout(false);
  this.ResumeLayout(false);

 }
 #endregion

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

 private void Form1_Load(object sender, System.EventArgs e)
 {
  DataTable dt = new DataTable("BindingTable");
  dt.Columns.Add("Column1");
  dt.Columns.Add("Column2");

  dt.Rows.Add(new object[] {"Hello", "World"});
  dt.Rows.Add(new object[] {"Goodbye", "Cruel World"});
  dt.Rows.Add(new object[] {"Greetings", "Earthling"});

  this.checkedListBox1.DataSource = dt;
  this.checkedListBox1.DisplayMember = "Column2";
  this.checkedListBox1.ValueMember = "Column1";

 }
}
}