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
import java.util.Collection;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import org.eclipse.birt.report.IBirtConstants;
import org.eclipse.birt.report.context.ScalarParameterBean;
import org.eclipse.birt.report.context.ViewerAttributeBean;
import org.eclipse.birt.report.model.api.ScalarParameterHandle;
import org.eclipse.birt.report.model.api.util.ParameterValidationUtil;
import org.eclipse.birt.report.service.api.IViewerReportDesignHandle;
import org.eclipse.birt.report.service.api.IViewerReportService;
import org.eclipse.birt.report.service.api.InputOptions;
import org.eclipse.birt.report.service.api.ParameterDefinition;
import org.eclipse.birt.report.service.api.ParameterGroupDefinition;
import org.eclipse.birt.report.service.api.ParameterSelectionChoice;
import org.eclipse.birt.report.service.api.ReportServiceException;
import org.eclipse.birt.report.utility.ParameterAccessor;
/**
 * Fragment help rendering scalar parameter.
 * <p>
 * 
 * @see org.eclipse.birt.report.presentation.aggregation.BaseFragment
 */
public class ComboBoxParameterFragment extends ScalarParameterFragment
{
	/**
	 * Protected constructor.
	 * 
	 * @param parameter