question on combobox

Hi All.
I have a problem with combobox, what I want is when combobox gets focus I need it to show the dropdown list
t.This is fine if the user selects the combobox via keystrokes but when the combobox is selected via mouse click it draws
the dropdown list twice. As I am trapping the enter event, I can see thats is called as well some other ?

the style is set to dropdownlist as they must select one from the list

I assume I must trap a mouse event so it doesn't draw the dropdown list because I will be in the enter event, but which one?

thanks for any input.
Code below.

P.S I did post this question to m.p.d.f.winform s but did not receive any replies.

using System;
using System.Drawing;
using System.Collecti ons;
using System.Componen tModel;
using System.Windows. Forms;


namespace test
{
/// <summary>
/// Summary description for Form1.
/// </summary>
public class Form1 : System.Windows. Forms.Form
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.Componen tModel.Containe r components = null;

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

//
// TODO: Add any constructor code after InitializeCompo nent call
//
}

/// <summary>
/// Clean up any resources being used.
/// </summary>
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Disp ose();
}
}
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 InitializeCompo nent()
{
this.cbp = new System.Windows. Forms.ComboBox( );
this.textBox1 = new System.Windows. Forms.TextBox() ;
this.SuspendLay out();
//
// cbp
//
this.cbp.DropDo wnStyle = System.Windows. Forms.ComboBoxS tyle.DropDownLi st;
this.cbp.Locati on = new System.Drawing. Point(208, 176);
this.cbp.Name = "cbp";
this.cbp.Size = new System.Drawing. Size(121, 21);
this.cbp.TabInd ex = 6;
//
// textBox1
//
this.textBox1.L ocation = new System.Drawing. Point(208, 136);
this.textBox1.N ame = "textBox1";
this.textBox1.T abIndex = 1;
this.textBox1.T ext = " ";
//
// Form1
//
this.AutoScaleB aseSize = new System.Drawing. Size(5, 13);
this.ClientSize = new System.Drawing. Size(792, 566);
this.Controls.A dd(this.textBox 1);
this.Controls.A dd(this.cbp);
this.Name = "Form1";
this.Load += new System.EventHan dler(this.Form1 _Load);
this.ResumeLayo ut(false);

}
#endregion

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

private System.Windows. Forms.TextBox textBox1;
private System.Windows. Forms.ComboBox cbp;
private void Form1_Load(obje ct sender, System.EventArg s e)
{
cbp.Items.Add(" Hello");
cbp.Items.Add(" Everyone");
cbp.DropDown+=n ew EventHandler(cb p_DropDown);
cbp.Enter+=new EventHandler(cb p_Enter);

cbp.MouseUp+=ne w MouseEventHandl er(cbp_MouseUp) ;

}

private void cbp_DropDown(ob ject sender, EventArgs e)
{
if (cbp.DroppedDow n==true)
return;
}

private void cbp_Enter(objec t sender, EventArgs e)
{
cbp.DroppedDown =true;
}
private void cbp_MouseUp(obj ect sender, MouseEventArgs e)
{
cbp.DroppedDown =true;
}
}

}