title: Highlight specific text in richtextbox
body: <p>I have a window form that contain a <code>listbox</code> and some <code>richtextboxex</code>. <code>listbox</code> contains some values. When I select any value from <code>listbox</code>, <code>richtextboxex</code> bind with data according to selected value.</p>
  
  <p>I have to highlight some text which is bind to <code>richtextbox</code> when I select a value from listbox, e.g.: </p>
  
  <blockquote>
    <p>Just a friendly reminder that you have &lt;&lt;OverdueInvCount>> overdue invoice(s), with an overdue balance of &lt;&lt;OverdueInvTotal>>. If you have any questions about the amount you owe, please give us a call and we’ll be happy to discuss it. If you’ve already sent your payment, please disregard this reminder.</p>
  </blockquote>
  
  <p>All data is coming from database.</p>
  
  <p>I want to highlight <code>&lt;&lt;OverdueInvCount&gt;&gt;</code> and <code>&lt;&lt;OverdueInvTotal&gt;&gt;</code> these words.</p>