title: XSD schema abstract type problem
body: <p>I have a problem with an xsd schema file. </p>
  
  <p>I have this abstract complex type on my schema: </p>
  
  <pre><code>&lt;complexType name="Action" abstract="true"&gt;
      &lt;sequence&gt;
          &lt;element name="actionType"&gt;
              &lt;complexType&gt;
                  &lt;choice&gt;
                      &lt;element name="ALARMACTION"/&gt;
                      &lt;element name="REPORTDATAACTION"/&gt;
                      &lt;element name="ENABLEOBSERVATIONACTION"/&gt;
                      &lt;element name="DISABLEOBSERVATIONACTION"/&gt;
                      &lt;element name="SETOBSERVATIONSCHEDULEACTION"/&gt;
              &lt;element name="VERIFYOVERTIMEACTION"/&gt;
                  &lt;/choice&gt;
              &lt;/complexType&gt;
          &lt;/element&gt;
      &lt;/sequence&gt;
  &lt;/complexType&gt;
  </code></pre>
  
  <p>This is a concrete implementation of Action abstract element:</p>
  
  <pre><code>&lt;complexType name="AlarmAction"&gt;
      &lt;complexContent&gt;
          &lt;extension base="ref:Action"&gt;
              &lt;sequence&gt;
                  &lt;element name="alarmCode" type="integer"/&gt;
                  &lt;element name="report" type="string"/&gt;
              &lt;/sequence&gt;
          &lt;/extension&gt;
      &lt;/complexContent&gt;
  &lt;/complexType&gt;
  </code></pre>
  
  <p>This element references the abstract Action element: </p>
  
  <pre><code>&lt;complexType name="Conclusion"&gt;
      &lt;sequence&gt;
          &lt;element minOccurs="0" name="observationSet" type="ref:ObservationSet"/&gt;
          &lt;element name="action" type="ref:Action"/&gt;
      &lt;/sequence&gt;
  &lt;/complexType&gt;
  </code></pre>
  
  <p>I got an error with this xml instance:</p>
  
  <pre><code>            &lt;Conclusion&gt;
                  &lt;observationSet&gt;
                      &lt;observationPhenomenum&gt;HIGH_HEARTBEAT&lt;/observationPhenomenum&gt;
                  &lt;/observationSet&gt;
                  &lt;action&gt;
                      &lt;actionType&gt;
                          &lt;ENABLEOBSERVATIONACTION&gt;&lt;/ENABLEOBSERVATIONACTION&gt;
                      &lt;/actionType&gt;
                  &lt;observationId&gt;1&lt;/observationId&gt;
                  &lt;observationId&gt;2&lt;/observationId&gt;
                  &lt;/action&gt;
          &lt;/Conclusion&gt;
  </code></pre>
  
  <p>The error on netbeans is this: cvc-type.2: The type definition cannot be abstract for element action. [104] </p>
  
  <p>Can someone help me?</p>