Bug 147852 [regression]Combo/listbox parameter doesn't work when put in parameter group
Description: Combo/listbox parameter doesn't work when put in parameter group Steps to reproduce: 1. New a prameter group 2. Insert a textbox parameter 3. Insert a combo/listbox parameter, input several values 4. Preview and select parameter values Expected result: Values can be selected Actual result: Once you selected a value from combo/listbox parameter list, the list would become empty.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/presentation/aggregation/parameter/ComboBoxParameterFragment.java
*            parameter definition reference.
	 */
	public ComboBoxParameterFragment( ParameterDefinition parameter )
	{
		super( parameter );
	}
	protected void prepareParameterBean( HttpServletRequest request,
			IViewerReportService service, ScalarParameterBean parameterBean,
			Locale locale ) throws ReportServiceException
	{
		ViewerAttributeBean attrBean = (ViewerAttributeBean) request
				.getAttribute( IBirtConstants.ATTRIBUTE_BEAN );
		assert attrBean != null;
		InputOptions options = new InputOptions( );
		options.setOption( InputOptions.OPT_REQUEST, request );
		Collection selectionList = null;
		ParameterDefinition paramDef = parameterBean.getParameter( );
		if ( paramDef.getGroup( ) != null && paramDef.getGroup( ).cascade( ) )
		{
			Map paramValues = attrBean.getParameters( );
			selectionList = getParameterSelectionListForCascadingGroup(
					attrBean.getReportDesignHandle( request ), service,
					paramValues, options );
		}
		else
			selectionList = service.getParameterSelectionList( attrBean
					.getReportDesignHandle( request ), options, parameter
					.getName( ) );
		parameterBean.setValueInList( false );
		if ( selectionList != null )