Bug 153405 Null parameter value is inconsistent between designer and preview
Description: Null parameter value is inconsistent between designer and preview Steps to reproduce: 1. New a report parameter, list-box, tick AllowNull. 2. Click New button, click OK without input anything. 3. Drag the parameter to Layout and preview Actual result: After step2, display text is "Null" and value is empty. However, when preview, the display text is "Null Value". Expected result: Display text and value should be consistent between Edit Parameter Dialog in Layout and Parameter dialog during preview.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/ParameterDialog.java
importValue.setEnabled( !inputParameter.getModuleHandle( )
				.getVisibleDataSets( )
				.isEmpty( ) );
		importValue.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				boolean defaultValueRemoved = true;
				String type = getSelectedDataType( );
				List choices = new ArrayList( );
				for ( Iterator iter = choiceList.iterator( ); iter.hasNext( ); )
				{
					SelectionChoice choice = (SelectionChoice) iter.next( );
					choices.add( choice.getValue( ) );
				}
				ImportValueDialog dialog = new ImportValueDialog( type, choices );
				if ( dialog.open( ) == OK )
				{
					String[] importValues = (String[]) dialog.getResult( );
					choiceList.clear( );
					for ( int i = 0; i < importValues.length; i++ )
					{
						SelectionChoice choice = StructureFactory.createSelectionChoice( );
						choice.setValue( importValues[i] );
						choiceList.add( choice );
						if ( defaultValue != null
								&& defaultValue.equals( importValues[i] ) )
						{
							defaultValueRemoved = false;
						}
					}