anchor.diff:        list = group
             .where((suggestion) => _suggestionFilter(suggestion, filterQuery))
             .take(limit);
  +    } else if (_shouldFilterEmpty) {
  +      list = group.take(limit);
       } else {
  -      list = group.take(limit);
  +      list = Iterable<T>.empty();
       }
       var filteredGroup = OptionGroup<T>.withLabelFunction(
           list.toList(growable: false),
  
positive.code: 
    final bool _shouldSort;
  
    /// The list of options and optionally a function to convert the option into a
    /// string that can be used for filtering the list.
    ///
  
negative.code:   ///
    /// If the data needs to be sorted, it should be passed in sorted. The option
    /// [shouldSort] is a simple way to apply the default sorting rules.
    ///
    /// Set [shouldFilterEmpty] to false if [filter] should return empty when the
    /// query is empty.
    StringSelectionOptions(List<T> options,
        {ItemRenderer<T> toFilterableString,
        StringSuggestionFilter<T> suggestionFilter,
        ItemRenderer<String> sanitizeString = _stringFormatSuggestion,
        bool shouldSort = false,
        bool shouldFilterEmpty = true})
        : this.withOptionGroups([OptionGroup(options)],
              toFilterableString: toFilterableString,
              suggestionFilter: suggestionFilter,
              sanitizeString: sanitizeString,
              shouldSort: shouldSort,
              shouldFilterEmpty: shouldFilterEmpty);
  
    StringSelectionOptions.withOptionGroups(List<OptionGroup<T>> optionGroups,
        {ItemRenderer<T> toFilterableString,
        StringSuggestionFilter<T> suggestionFilter,
        ItemRenderer<String> sanitizeString = _stringFormatSuggestion,
        bool shouldSort = false,
        bool shouldFilterEmpty = true})
        : _toFilterableString =
              toFilterableString ?? _defaultRenderer(sanitizeString),
          _shouldSort = shouldSort,
          _shouldFilterEmpty = shouldFilterEmpty,
          _sanitizeString = sanitizeString,
          super(optionGroups) {
      _suggestionFilter =
  