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
if ( PARAM_CONTROL_COMBO.equals( newControlType ) )
						{
							newControlType = DesignChoiceConstants.PARAM_CONTROL_LIST_BOX;
							selectedParameter.setMustMatch( true );
						}
						else if ( PARAM_CONTROL_LIST.equals( newControlType ) )
						{
							newControlType = DesignChoiceConstants.PARAM_CONTROL_LIST_BOX;
							selectedParameter.setMustMatch( false );
						}
						else
						{
							selectedParameter.setProperty( ScalarParameterHandle.MUCH_MATCH_PROP,
									null );
						}
						selectedParameter.setControlType( newControlType );
					}
					catch ( SemanticException e1 )
					{
						ExceptionHandler.handle( e1 );
					}
				}
			}
		} );
		createLabel( propertiesGroup, LABEL_DEFAULT_VALUE, maxStrLengthProperty );
		defaultValueEditor = new Text( propertiesGroup, SWT.BORDER );
		defaultValueEditor.setLayoutData( new GridData( GridData.FILL_HORIZONTAL ) );
	}
	private void createOptionsPart( Composite parent )
	{