Tooltip on Combobox disappears - Windows Forms bug?

[Jake Montgomery]

I am using .NET 2.0 forms and running on Windows XP SP2. When I have a
tooltip on a combo box, and the combo box is expanded (“dropped down”)
using the arrow, it will no longer display it’s tooltip, no matter how
long I hover. Even if I move off the control and back it will still not
display its tooltip. If I then go to another control that has tootips,
then back to the combobox, it will again display its tooltip, until the
next time it is expanded.

Below is a small sample that has this bug (on my machine anyway.) It is
simply the standard VS8.0 generated code, condensed. Strangely, if I
remove the EnableVisualSty les() line, then the tootips seem to work
correctly.

I could not find any information about this bug. I am curious if anyone
else has come across it, and if there is a solution? Any help appreciated.
======= Buildable Code Sample Below

using System;
using System.Collecti ons.Generic;
using System.Windows. Forms;

namespace ComboTest
{
static class Program
{
[STAThread]
static void Main()
{
Application.Ena bleVisualStyles ();
Application.Run (new Form1());
}
}

class Form1 : Form
{
public Form1()
{
InitializeCompo nent();
}

private System.Componen tModel.IContain er components = null;
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Disp ose();
}
base.Dispose(di sposing);
}

private void InitializeCompo nent()
{
this.components = new System.Componen tModel.Containe r();
this.comboBox1 = new System.Windows. Forms.ComboBox( );
this.toolTip1 = new System.Windows. Forms.ToolTip(t his.components) ;
this.button1 = new System.Windows. Forms.Button();
this.SuspendLay out();
// comboBox1
this.comboBox1. DropDownStyle =
System.Windows. Forms.ComboBoxS tyle.DropDownLi st;
this.comboBox1. FormattingEnabl ed = true;
this.comboBox1. Location = new System.Drawing. Point(12, 59);
this.comboBox1. Name = "comboBox1" ;
this.comboBox1. Size = new System.Drawing. Size(121, 21);
this.comboBox1. TabIndex = 0;
this.toolTip1.S etToolTip(this. comboBox1, "Combo Tooltip");
// button1
this.button1.Lo cation = new System.Drawing. Point(12, 12);
this.button1.Na me = "button1";
this.button1.Si ze = new System.Drawing. Size(75, 23);
this.button1.Ta bIndex = 1;
this.button1.Te xt = "button1";
this.toolTip1.S etToolTip(this. button1, "Button tip.");
this.button1.Us eVisualStyleBac kColor = true;
// Form1
this.AutoScaleD imensions = new System.Drawing. SizeF(6F, 13F);
this.AutoScaleM ode = System.Windows. Forms.AutoScale Mode.Font;
this.ClientSize = new System.Drawing. Size(292, 266);
this.Controls.A dd(this.button1 );
this.Controls.A dd(this.comboBo x1);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayo ut(false);
}
private System.Windows. Forms.ComboBox comboBox1;
private System.Windows. Forms.ToolTip toolTip1;
private System.Windows. Forms.Button button1;
}
}
====== END Code Sample