anchor.diff:      open = !open;
       if (open) {
         if (children.isEmpty) {
  -        children = generatorFns.map((a) => a()).toList();
  +        children.addAll(generatorFns.map((a) => a()));
           // Resort because more children were generated.
           sort(sortComparator);
         }
  
positive.code:   HtmlElement parentElement;
  
    // The depth of this row in the overall tree.
    int level;
  
    // Stored comparator for the sorting function.
    // Because the tree is generated lazily, this needs to be stored to
  
negative.code:   bool open = false;
  
    // A pointer into the data
    final Map<String, dynamic> data;
  
    String get id => data['id'];
  
    // A list of 'soon to be children' row functions.
    // This is the key part of having the entire data
    // structure be lazily evaluated.
    final List<GenerateRowFunction> generatorFns = <GenerateRowFunction>[];
  
    // After the generatorFns array is processed when this
    // node is expanded, this children array will be filled with
    // [LogicalRow]s
    final List<LogicalRow> children = <LogicalRow>[];
  
    // If this row is sortable.  An example of a non-sortable row
    // would be the 'code' and 'parameters' rows of a function
  