private void button9_Click(object sender, EventArgs e)
{
Win32API.CloseWindow(button1.Handle);
Win32API.CloseWindow(button2.Handle);
Win32API.CloseWindow(button3.Handle);
System.Threading.Thread.Sleep(3 * 1000);
uint result = Win32API.ArrangeIconicWindows(this.Handle);
Console.WriteLine(result);
}