C#

private void button1_Click(object sender, System.EventArgs e)<br />
{<br />
try<br />
{<br />
this.richTextBox1.Clear();<br />
for(int i=0; i<200; i++)<br />
{<br />
this.richTextBox1.SelectedText = "Index = " + i.ToString() + "\r\n"; // 1. try<br />
// this.richTextBox1.AppendText("Index = " + i.ToString()+ "\r\n"); // 2. try<br />
// this.richTextBox1.Text += "Index = " + i.ToString()+ "\r\n"; // 3. try<br />
this.richTextBox1.ScrollToCaret();<br />
}<br />
}<br />
catch{}<br />
}

 FrmHelp frmHelp = new FrmHelp();
 frmHelp.HelpTextBox.Text = "This is help";
 frmHelp.ShowDialog();
and in the load event i changed the focus to button

  private void FrmHelp_Load(object sender, EventArgs e)
        {
           buttonClose.Focus();           
        }