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
inputParameter = (ScalarParameterHandle) input;
	}
	protected boolean initDialog( )
	{
		Assert.isNotNull( inputParameter );
		nameEditor.setText( inputParameter.getName( ) );
		if ( !StringUtil.isBlank( inputParameter.getPromptText( ) ) )
		{
			promptTextEditor.setText( inputParameter.getPromptText( ) );
		}
		helpTextEditor.setText( UIUtil.convertToGUIString( inputParameter.getHelpText( ) ) );
		if ( inputParameter.getValueType( )
				.equals( DesignChoiceConstants.PARAM_VALUE_TYPE_STATIC ) )
		{
			staticRadio.setSelection( true );
			for ( Iterator iter = inputParameter.getPropertyHandle( ScalarParameterHandle.SELECTION_LIST_PROP )
					.iterator( ); iter.hasNext( ); )
			{
				SelectionChoiceHandle choiceHandle = (SelectionChoiceHandle) iter.next( );
				choiceList.add( choiceHandle.getStructure( ) );
			}
		}
		else
		{
			dynamicRadio.setSelection( true );
		}
		defaultValue = inputParameter.getDefaultValue( );
		if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
		{
			try