title: Textbox.SelectionStart
body: <p>I'm trying to use the SelectionStart and SelectionLength properties for a textbox. It is having no effect, but there are no errors either. It's actually part of a background worker ProgressChanged method, but I've tried the SelectionStart and SelectionLength in isolation in a test solution and it is the same.. nothing happens..</p>
  
  <p>Any ideas? Thanks!!!</p>
  
  <pre><code>private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) 
  {
      // Update the GUI as the music is playing
      textBox1.SelectionStart = ((int)e.UserState);
      textBox1.SelectionLength = (1);
  }
  </code></pre>