title: How to get only NEW text from TextBox?
body: <pre><code>private void tbLog_TextChanged(object sender, TextChangedEventArgs e)
  {
      //Get only NEW text added to Log
  }
  
  /*
      LOG
      old message...
      old message...
      old message...
      old message...
      NEW message...
      NEW message...
      NEW message...
      NEW message...
      NEW message...
  */  
  </code></pre>
  
  <p>How to I get only NEW text from the TextBox? </p>