title: ExtJS: add button to htmleditor
body: <p>I am using ExtJS and I have a htmleditor in my form. I would like to add a custom button to that element (for example after all other buttons like alignments, font weights, ...). This button should basically insert a standard template in the htmlfield. Being this template html, the behaviour of the button should be like this</p>
  
  <ul>
  <li>Switch to HTML mode (like when pressing Source button)</li>
  <li>Insert something</li>
  <li>Switch back to WYSIWYG mode (like when pressing the Source button again)</li>
  </ul>
  
  <p>Thanks for your attention</p>