title: How do I identify a Faktor-IPS extension property in a validation message?
body: <p>I've created an extension property and added some validation code - but how do I identify the extension property within the message so the error marker is placed on the field for my extension property?</p>
  <p>Here is my code:</p>
  <pre><code>@Override
      public MessageList validate(IIpsObjectPartContainer ipsObjectPart, Object value) throws CoreException {
          MessageList ml = new MessageList();
          
          if (!(value instanceof Bearbeitbarkeit)) {
              ml.newError(MSG_WRONG_TYPE, &quot;Der Typ des Werts passt nicht zum Extension Property&quot;, ipsObjectPart);
          }
          
          return ml;
      }
  </code></pre>