title: RichTextBox invisible selectable character at end of string
body: <p>When selecting text in a RichTextBox using the mouse, or arrow keys + shift, I can select an extra blank character at the end of the string.  To reproduce:</p>
  
  <ul>
  <li><p>type a few characters (or nothing at all) in a RichTextBox </p></li>
  <li><p>set the cursor to the end of the string</p></li>
  <li><p>hold shift and press the right arrow key</p></li>
  </ul>
  
  <p>You'll see a narrow highlighted selection appear, which cannot be deleted.  </p>
  
  <p>This causes a problem in my application because the SelectionFont property returns null when the extra character is selected along with some valid text.  Any ideas on how to disable this extra character, or work around it otherwise?</p>
  
  <p>c# winforms, visual studio 2010</p>