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
DataPointHints dph = (DataPointHints) source.getSource( );
			if ( tg.getAction( ).getType( ) == ActionType.SHOW_TOOLTIP_LITERAL )
			{
				
				String toolText = ( (TooltipValue) tg.getAction( ).getValue( ) ).getText( );
				
				
				
				if ( toolText == null )
				{
					( (TooltipValue) tg.getAction( ).getValue( ) ).setText( dph.getDisplayValue( ) );
				}
			}
			else if ( tg.getAction( ).getType( ) == ActionType.URL_REDIRECT_LITERAL )
			{
				
				final URLValue uv = (URLValue) tg.getAction( ).getValue( );
				String sBaseURL = uv.getBaseUrl( );
				if ( sBaseURL == null )
				{
					sBaseURL = ""; 
				}
				final StringBuffer sb = new StringBuffer( sBaseURL );
				char c = '?';
				if ( sBaseURL.indexOf( c ) != -1 )
				{
					c = '&';
				}
				if ( uv.getBaseParameterName( ) != null
						&& uv.getBaseParameterName( ).length( ) > 0 )