Bug 176582 "Show Lines as Curves" does not work correctly for Area Chart [0001]
Description: "Show Lines as Curves" does not work correctly for Area Chart. Build number: 2.2.0.v20070307-1128 Steps to reproduce: 1. New a Area Chart. 2. In "Format Chart" tab, select Series->Value (Y) Series, tick and untick "Show Lines as Curves" checkbox. Expected result: Null value point e is treated the same when tick and untick "Show Lines as Curves" checkbox. Actual result: Null value point e is treated differently (see the screenshot). Error log: N/A
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/render/BaseRenderer.java
renderSeparator( ipr,
									lg,
									liSep,
									dBaseX + lih.getLeft( ),
									dBaseY + lih.getTop( ),
									bo.getHeight( ),
									Orientation.VERTICAL_LITERAL );
						}
					}
				}
			}
			else
			{
				throw new ChartException( ChartEnginePlugin.ID,
						ChartException.RENDERING,
						"exception.illegal.legend.direction", 
						new Object[]{
							d.getName( )
						},
						Messages.getResourceBundle( rtc.getULocale( ) ) );
			}
		}
		else if ( o.getValue( ) == Orientation.HORIZONTAL )
		{
			if ( bPaletteByCategory )
			{
				SeriesDefinition sdBase = null;
				if ( cm instanceof ChartWithAxes )
				{