title: Customizing pieces management modal in Apostrophe CMS
body: <p>I am using the <a href="https://github.com/apostrophecms/apostrophe-samples" rel="nofollow noreferrer"><code>apostrophe-samples</code> Github project</a> to do some tests regarding the pieces modal customization. So far, I've added filters <a href="https://apostrophecms.org/docs/tutorials/getting-started/reusable-content-with-pieces.html#filters-for-the-quot-manage-quot-modal" rel="nofollow noreferrer">as explained in the tutorials</a>, and added columns as seen in the <code>apostrophe-pieces</code> source code (I think it would be an interesting topic to add to the tutorials, IMHO).</p>
  
  <p>However, I have a couple of doubts, given the example that <em>specialists</em> <code>joinByArray</code> <em>products</em> and <em>products</em> <code>joinByArrayReverse</code> <em>specialists</em>:</p>
  
  <ul>
  <li>Can columns be sorted in any way through the UI (e.g., an option that enables sorting by clicking the table header) or does it rely entirely on the piece's <code>defaultSort</code>?</li>
  <li>Can other fields other than the title be added as filters? I was able to add <code>_specialists</code> as products filter, displaying the title, but I'm wondering if a different field could be used.</li>
  <li>Can <strong>reverse</strong> joins be added as filters? As said, I was able to add <code>_specialists</code> as products filter, but not the other way around.</li>
  <li>Can joins/reverse joins be added as columns? If I add '_specialists' I column, I get displayed an array like <code>[Object]</code>, not the title as in the filter.</li>
  </ul>