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
table.setLinesVisible( true );
		table.setHeaderVisible( true );
		table.addKeyListener( new KeyAdapter( ) {
			public void keyReleased( KeyEvent e )
			{
				
				if ( e.keyCode == SWT.DEL )
				{
					deleteRow( );
				}
			}
		} );
		int[] columnWidths = new int[]{
				160, 115, 135, 145,
		};
		String[] columns = new String[]{
				COLUMN_NAME, COLUMN_DATA_SET, COLUMN_VALUE, COLUMN_DISPLAY_TEXT
		};
		cellEditors = new CellEditor[]{
				new TextCellEditor( table ),
				new ComboBoxCellEditor( table,
						ChoiceSetFactory.getDataSets( ),
						SWT.READ_ONLY ),
				new ComboBoxCellEditor( table, new String[0], SWT.READ_ONLY ),
				new ComboBoxCellEditor( table, new String[0], SWT.READ_ONLY ),
		};
		for ( int i = 0; i < columns.length; i++ )
		{
			TableColumn column = new TableColumn( table, SWT.LEFT );
			column.setResizable( true );