Bug 177504 Engine doesn't provide SubQuery for extended item
Engine doesn't provide SubQuery for extended item, so chart can't use container's binding to execute the query. If possible, engine could provide an option for extended item to choose whether engine could create the query, so extended item won't create SubQuery by itself.
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ExtendedItemExecutor.java
{
	protected static Logger logger = Logger
			.getLogger( ExtendedItemExecutor.class.getName( ) );
	protected IReportItemExecutor executor;
	
	/**
	 * @param context
	 *            the engine execution context
	 * @param visitor
	 *            visitor class used to visit the extended item
	 */
	public ExtendedItemExecutor( ExecutorManager manager )
	{
		super( manager );
	}
	/**
	 * <li> create an foreign content
	 * <li> push it to content
	 * <li> execute the query if any
	 * <li> intialize the content object