Bug 161222 Decoration label should be optional in Gantt Chart
It should not be mandatory to specify a decoration label for Gantt Charts, this can be left blank. Currently the UI and Engine enforce a data definition to be specified for it.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/internal/datafeed/ResultSetWrapper.java
needBaseGrouping = false;;
		}
		
		final Series seBaseDesignTime = sd.getDesignTimeSeries( );
		final Query q = (Query) seBaseDesignTime.getDataDefinition( ).get( 0 );
		final int iSortColumnIndex = ( (Integer) htLookup.get( q.getDefinition( ) ) ).intValue( );
		SortOption so = null;
		if ( !sd.isSetSorting( ) )
		{
			if ( needBaseGrouping )
			{
				logger.log( ILogger.WARNING,
						Messages.getString( "warn.unspecified.sorting", 
								new Object[]{
									sd
								},
								ULocale.getDefault( ) ) );
				so = SortOption.ASCENDING_LITERAL;
			}
		}
		else
		{
			so = sd.getSorting( );
		}
		new GroupingSorter( ).sort( workingResultSet,
				iSortColumnIndex,
				so,
				iaGroupBreaks );
		
		if ( !needBaseGrouping )