title: Joomla Article add custom Options
body: <p>I am trying to add extra fields to the Backend page of Joomla-Articles. Because I want to use them in my layout override. Therefore I tried to change parameters in: </p>
  
  <pre><code>/html/components/com_content/views/article/tmpl/default.xml
  </code></pre>
  
  <p>Now my questions:</p>
  
  <ol>
  <li>Why are there no changes visible, when changing anything in this file?</li>
  <li>Is it possible to overrite this xml-file with an Joomla layout-overwrite in my Template?</li>
  <li>I only want to display this fields to Articles of an custom category. Is this possible? (Maybe via extended layout overwrite?)</li>
  </ol>
  
  <p>Thanks for your help guys, 
  Ripei </p>