Bug 144106 [Regression]Parameter request page pops up twice while running the report with cascading parameter
Steps to reproduce: 1.Add a cascading parameter group with a parameter 2.Preview Expected result: The parameter request page just pops up once for input value Actual result: The parameter request page pops up twice when inputting parameter value
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
{
			e.printStackTrace( );
		}
		
		ScalarParameterHandle parameter = (ScalarParameterHandle) findParameter( paramName );
		
		if ( defaultValueObj != null && parameter != null )
		{
			defalutValue = ParameterValidationUtil.getDisplayValue( null,
					parameter.getPattern( ), defaultValueObj, locale );
		}
		
		if ( defalutValue == null && parameter != null )
		{
			defalutValue = parameter.getDefaultValue( );
		}
		return defalutValue;
	}
	/**
	 * if parameter existed in config file, return the correct parameter name
	 * 
	 * @param configVarName
	 *            String
	 * @return String
	 */
	private String getParameterName( String configVarName )
			throws ReportServiceException
	{
		assert reportDesignHandle != null;
		String paramName = null;