Bug 198031 Legend interactivity does not work correctly for drill-throughs
Under Value (Y) Series enable interactivity for the event "Mouse Click" Set action to Hyperlink The type of the hyperlink is Drill-through and the target is the a sub-report Pass parameter to sub-report as row["value_of_the_legend_item"] Suppose there are 3 values, x,y and z No matter which legend item you click (x, y or z), z gets passed as param to the subreport
chart/org.eclipse.birt.chart.reportitem.ui/src/org/eclipse/birt/chart/reportitem/ui/ChartReportItemBuilderImpl.java
protected void configureExpressionBuilder(
							ExpressionBuilder builder )
					{
						builder.setExpressionProvier( new ExpressionProvider( (ExtendedItemHandle) context ) );
					}
				};
				try
				{
					hb.setInputString( value, extendedHandle );
					if ( sTitle != null )
					{
						hb.setTitle( hb.getTitle( ) + " - " + sTitle ); 
					}
					if ( hb.open( ) == Window.OK )
					{
						value = hb.getResultString( );
					}
				}
				catch ( Exception e )
				{
					throw new ChartException( ChartReportItemUIActivator.ID,
							ChartException.UNDEFINED_VALUE,
							e );
				}
				break;
			case COMMAND_EXPRESSION_CHART_DATAPOINTS :
			case COMMAND_EXPRESSION_DATA_BINDINGS :
			case COMMAND_EXPRESSION_TRIGGERS_SIMPLE :
			case COMMAND_EXPRESSION_TRIGGERS_DATAPOINTS :
				shell = new Shell( Display.getDefault( ), SWT.DIALOG_TRIM