code: @Override
      protected void init(Object target, PropertyInfo propInfo, PropertyGrid propGrid) {
          super.init(target, propInfo, propGrid);
  
          Iterable<?> iter = (Iterable<?>) propInfo.getPropertyType().getSerializer();
  
          for (Object value : iter) {
              appendItem(value.toString(), value);
          }
  
      }
docs: Initialize the list, based on the configuration data which can specify an enumeration class,
  an iterable class, or the id of an iterable bean.