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/ParameterDialog.java
pattern = formatCategroy;
			}
			if ( DesignChoiceConstants.PARAM_TYPE_DATETIME.equals( getSelectedDataType( ) ) )
			{
				Date date = DataTypeUtil.toDate( string, ULocale.US );
				DateFormatter formatter = new DateFormatter( pattern );
				string = formatter.format( date );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_FLOAT.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toDouble( string )
						.doubleValue( ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_DECIMAL.equals( getSelectedDataType( ) ) )
			{
				string = new NumberFormatter( pattern ).format( DataTypeUtil.toBigDecimal( string ) );
			}
			else if ( DesignChoiceConstants.PARAM_TYPE_STRING.equals( getSelectedDataType( ) ) )
			{
				string = new StringFormatter( pattern ).format( string );
			}
		}
		catch ( BirtException e )
		{
			
		}
		return string;
	}
	/**
	 * Check if the specified value is valid