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
{
				choice.setValue( convertToStandardFormat( choice.getValue( ) ) );
				choiceList.add( choice );
				return true;
			}
			return false;
		}
		public boolean removeItem( Object[] elements )
		{
			for ( int i = 0; i < elements.length; i++ )
			{
				if ( isDefaultChoice( (SelectionChoice) elements[i] ) )
				{
					changeDefaultValue( null );
				}
				choiceList.remove( elements[i] );
			}
			return true;
		}
	};
	private Text listLimit;
	/**
	 * Create a new parameter dialog with given title under the active shell
	 * 
	 * @param title
	 *            the title of the dialog
	 */
	public ParameterDialog( String title )
	{
		this( UIUtil.getDefaultShell( ), title );