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/data/dte/ReportQueryBuilder.java
*            the item.
		 * @return true if it needs query.
		 */
		private boolean needQuery( ReportItemDesign item, IBaseQueryDefinition query )
		{
			DesignElementHandle handle = item.getHandle( );
			if ( handle instanceof ReportItemHandle )
			{
				ReportItemHandle designHandle = (ReportItemHandle) item.getHandle( );
				if ( designHandle.columnBindingsIterator( ).hasNext( ) )
				{
					return true;
				}
				if ( designHandle instanceof ListingHandle )
				{
					return true;
				}
			}
			HighlightDesign highlight = item.getHighlight( );
			if ( query == null && highlight != null
					&& highlight.getRuleCount( ) > 0 )
			{
				return true;
			}
			return false;
		}
		
		private void addSortAndFilter( ReportItemDesign item, BaseQueryDefinition query )
		{
			if ( item instanceof ListingDesign )