title: How insert multiline text into a RichTextBox?
body: <p>I'm using a <code>Xceed.Wpf.Toolkit.RichTextBox</code> that displays text saved in RTF. I've got a contextual menu that add some multi lines text at the caret position using this code</p>
  
  <pre><code>var text = "Line1" + Environment.NewLine + "Line2"
  richTextBox.CaretPosition.InsertTextInRun(text);
  </code></pre>
  
  <p>It displays as I expect</p>
  
  <pre><code>Line1
  Line2
  </code></pre>
  
  <p>When I save and reload the text (saved in RTF), it displays as this:</p>
  
  <pre><code>Line1Line2
  </code></pre>
  
  <p>When I look in the RTF code, it is saved without the CR and LF... </p>
  
  <p>Why my CR/LF vanished? What is the solution to insert multi line text at the caret position?</p>