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
if ( !canBeNull( ) || !containValue( null, null, COLUMN_VALUE ) )
				{
					
					
					errorMessage = ERROR_MSG_NO_DEFAULT_VALUE;
				}
			}
		}
		if ( errorMessage != null )
		{
			errorMessageLine.setText( errorMessage );
			errorMessageLine.setImage( ERROR_ICON );
		}
		else
		{
			errorMessageLine.setText( "" ); 
			errorMessageLine.setImage( null );
		}
		if ( promptMessageLine != null && !promptMessageLine.isDisposed( ) )
		{
			if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
			{
				promptMessageLine.setText( LABEL_DATETIME_PROMPT );
			}
			else
			{
				promptMessageLine.setText( "" ); 
			}
		}