Bug 211703 Support muti-view on report item.
As title described.
xtab/org.eclipse.birt.report.item.crosstab.core/src/org/eclipse/birt/report/item/crosstab/core/de/internal/CrosstabReportItemTask.java
return;
		
		
		if ( viewElement.getContainer( ) != null
				&& !viewElement.getElement( ).isContentOf(
						crosstab.getModelHandle( ).getElement( ) ) )
		{
			throw new PropertyValueException( crosstab.getModelHandle( )
					.getElement( ), crosstab.getModelHandle( ).getPropertyDefn(
					MULTI_VIEWS_PROP ), null,
					PropertyValueException.DESIGN_EXCEPTION_ITEM_NOT_FOUND );
		}
		CommandStack stack = crosstab.getModuleHandle( ).getCommandStack( );
		stack.startTrans( null );
		try
		{
			MultiViewsHandle multiView = getMultiViews( );
			if ( multiView == null )
			{
				multiView = crosstab.getModelHandle( ).getElementFactory( )
						.newMultiView( );
				crosstab.getModelHandle( ).setProperty( MULTI_VIEWS_PROP,
						multiView );
			}
			
			
			if ( viewElement.getContainer( ) != null
					&& !viewElement.getElement( ).isContentOf(
							multiView.getElement( ) ) )
			{