Bug 188029 Top face is missing in Area chart of 2D+ with negative values
Top face is missing in Area chart of 2D+ with negative values. Please see attached screenshot.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/computation/withaxes/StackedSeriesLookup.java
{
			iSharedUnitIndex = 0;
			iSharedUnitCount = 0;
			sgSingle = null; 
			el = axaOrthogonal[i].getSeriesDefinitions( );
			alSGCopies = new ArrayList( 4 );
			iSharedUnitCount = 0;
			for ( int j = 0; j < el.size( ); j++ ) 
			{
				sd = (SeriesDefinition) el.get( j );
				alSeries = sd.getRunTimeSeries( );
				iSeriesCount = alSeries.size( );
				if ( iSeriesCount > 1 )
				{
					bStackedSet = false;
					sg = null;
					for ( int k = 0; k < iSeriesCount; k++ ) 
					{
						se = (Series) alSeries.get( k );
						dsi = new DataSetIterator( se.getDataSet( ) );
						iDataSetCount = dsi.size( );
						if ( ssl.iCachedUnitCount == 0 )
						{
							ssl.iCachedUnitCount = iDataSetCount;
						}
						else if ( ssl.iCachedUnitCount != iDataSetCount )
						{
							throw new IllegalArgumentException( MessageFormat.format( Messages.getResourceBundle( 
									rtc.getULocale( ) )
									.getString( "exception.runtime.dataset.count.mismatch" ),