title: dynamically disable/enable inputs in activiti explorer
body: <p>is there any way to dynamically enable/disable inputs (form properties) in activiti explorer?
  I'm trying to do it like:</p>
  
  <pre><code>&lt;activiti:formProperty id="field" name="field" writable="${is_field_writable}"&gt;&lt;/activiti:formProperty&gt;
  </code></pre>
  
  <p>but it's not working</p>