Bug 140534 [Smoke]Can't changed the value of parameter use show report parameter
Details: [Smoke]Can't changed the value of parameter use show report parameter Step: 1. New a parameter. 2. Change display type to list box. 3. Insert some value into selection value and set the first value to default value. 4. Drop the parameter inro layout 5. Preview and press show report parameter, change the value and press OK. Actual result: The value can't be changed.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
}
	/**
	 * Get report service instance.
	 */
	protected IViewerReportService getReportService( )
	{
		return BirtReportServiceFactory.getReportService( );
	}
	/**
	 * Clear our resources.
	 * 
	 * @exception Throwable
	 * @return
	 */
	protected void __finalize( ) throws Throwable
	{
	}
	/**
	 * get parameter object.
	 * 
	 * @param request
	 * @param parameterObj
	 * @exception Throwable
	 * @return
	 */
	protected Object getParamValueObject( HttpServletRequest request,
			ParameterDefinition parameterObj ) throws ReportServiceException
	{
		String paramName = parameterObj.getName( );
		String format = parameterObj.getDisplayFormat( );