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
{
			
			ScalarParameterHandle parameterHandle = (ScalarParameterHandle) attrBean
					.findParameter( parameter.getName( ) );
			for ( Iterator iter = selectionList.iterator( ); iter.hasNext( ); )
			{
				ParameterSelectionChoice selectionItem = (ParameterSelectionChoice) iter
						.next( );
				
				String value = ParameterValidationUtil
						.getDisplayValue( selectionItem.getValue( ) );
				if ( value == null )
					continue;
				
				String label = selectionItem.getLabel( );
				if ( label == null || label.length( ) <= 0 )
				{
					
					
					label = ParameterValidationUtil.getDisplayValue( null,
							parameterHandle.getPattern( ), selectionItem
									.getValue( ), attrBean.getLocale( ) );
				}
				if ( label != null )
				{
					parameterBean.getSelectionList( ).add( label );
					parameterBean.getSelectionTable( ).put( label, value );
				}
				if ( value != null && value.equals( parameterBean.getValue( ) ) )
				{