Bug 180864 Change Allow Null option in Cascading Group.[0705]
Description: Change Allow Null option in Cascading Group. Build number:2.2.0.v20070404 Steps to reproduce: 1. New a cascading group and add sub parameter. Expected result: Is Required option in cascading group definition dialog. Actual result: Allow null value option in Cascading Group definition dialog Error log:N/A
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
dataTypeChooser.setItems( ChoiceSetFactory.getDisplayNamefromChoiceSet( DATA_TYPE_CHOICE_SET ) );
		dataTypeChooser.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )
			{
				if ( selectedParameter != null
						&& selectedParameter != newParameter )
				{
					changeDataType( DATA_TYPE_CHOICE_SET.findChoiceByDisplayName( dataTypeChooser.getText( ) )
							.getName( ) );
					try
					{
						selectedParameter.setDataType( DATA_TYPE_CHOICE_SET.findChoiceByDisplayName( dataTypeChooser.getText( ) )
								.getName( ) );
					}
					catch ( SemanticException e1 )
					{
						ExceptionHandler.handle( e1 );
					}
				}
			}
		} );
		createLabel( propertiesGroup, LABEL_DISPLAY_TYPE, maxStrLengthProperty );
		displayTypeChooser = new Combo( propertiesGroup, SWT.DROP_DOWN
				| SWT.READ_ONLY );
		displayTypeChooser.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
		displayTypeChooser.setItems( new String[]{
				DISPLAY_NAME_CONTROL_LIST, DISPLAY_NAME_CONTROL_COMBO
		} );
		displayTypeChooser.addSelectionListener( new SelectionAdapter( ) {
			public void widgetSelected( SelectionEvent e )