title: Unable to hide columns in Flex
body: <p>What I am trying to do is hide an entire column if the content is all null.</p>
  
  <pre><code>&lt;mx:DataGrid width="100%" dataProvider="{service}" id="dg1"&gt;
      &lt;mx:columns&gt;
          &lt;mx:DataGridColumn headerText="Location Origin" dataField="originLocation" visible="{data.originLocationExists}" /&gt;
          &lt;mx:DataGridColumn headerText="Location Destination" dataField="destinationLocation" visible="{data.destinationLocationExists}" /&gt;  
          &lt;mx:DataGridColumn headerText="Location Group Origin" dataField="originLocationGroup" visible="{data.originLocationGroupExists}" /&gt;
          &lt;mx:DataGridColumn headerText="Location Group Destination" dataField="destinationLocationGroup" visible="{data.destinationLocationGroupExists}"/&gt;               
      &lt;/mx:columns&gt;
  &lt;/mx:DataGrid&gt;
  </code></pre>
  
  <p>In the sample above, sometimes all the data in the "Location Origin" will be null, so under the visible property I put a value which is either true or false depending on the data. But even when all the data is null and the visible property equals false, it still stays visible.</p>
  
  <p>What can I do to fix this? And I am running in Flex 3.2</p>