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 ( refresh )
			{
				refreshValueTable( );
			}
		}
	}
	private boolean canBeBlank( )
	{
		boolean canBeBlank = false;
		if ( PARAM_CONTROL_LIST.equals( getSelectedControlType( ) )
				|| DesignChoiceConstants.PARAM_CONTROL_TEXT_BOX.equals( getSelectedControlType( ) ) )
		{
			if ( dirtyProperties.containsKey( CHECKBOX_ALLOW_BLANK ) )
			{
				canBeBlank = ( (Boolean) dirtyProperties.get( CHECKBOX_ALLOW_BLANK ) ).booleanValue( );
			}
			else
			{
				canBeBlank = inputParameter.allowBlank( );
			}
		}
		return canBeBlank;
	}
	private boolean canBeNull( )
	{
		boolean canBeNull = false;
		if ( dirtyProperties.containsKey( CHECKBOX_ALLOW_NULL ) )
		{
			canBeNull = ( (Boolean) dirtyProperties.get( CHECKBOX_ALLOW_NULL ) ).booleanValue( );
		}