title: 3 state checkbox in advancedDataGrid when grouped using data as arrayCollection
body: <p>I am looking for a 3 state checkbox added in advancedDataGrid when data is grouped, similar to the one i find in the search</p>
  
  <p><a href="http://techrays.wordpress.com/2008/02/18/a-3-state-checkbox-in-an-advanceddatagrid-itemrenderer/" rel="nofollow">http://techrays.wordpress.com/2008/02/18/a-3-state-checkbox-in-an-advanceddatagrid-itemrenderer/</a></p>
  
  <p>this is really good other than its not working for an arrayCollection as a data provider, as it is using the XMLListCollection</p>
  
  <p>I am not sure what changes need to be made in the file to make it work for arrayCollection </p>
  
  <p>Please help!!!!</p>