Bug 153523 OK button in parameter dialog is enabled without default value in combo-box
Description: OK button in parameter dialog is enabled without default value in combo-box Steps to reproduce: 1. New a report parameter, combo-box. 2. Click New button, input abc as value, click OK 3. Set abc as default value and close Edit Parameter dialog. 4. New a data source and dataset 5. Edit the parameter, remove abc value and import values from dataset Expected result: OK button is disabled for there is no default value. Actual result: OK button is enabled.
UI/org.eclipse.birt.report.designer.ui/src/org/eclipse/birt/report/designer/ui/dialogs/CascadingParametersDialog.java
{
					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 );
			column.setText( columns[i] );
			column.setWidth( columnWidths[i] );
		}
		table.setLayoutData( data );
		valueTable = new TableViewer( table );
		valueTable.setCellEditors( cellEditors );
		valueTable.setColumnProperties( columns );