anchor.diff:  
     final TreemapNode rootNode;
   
  +  final bool autoExpandRoot;
  +
     final TreeColumnData<TreemapNode> treeColumn;
     final ColumnData<TreemapNode> sortColumn;
     final List<ColumnData<TreemapNode>> columns;
   
     @override
     Widget build(BuildContext context) {
  +    if (autoExpandRoot) {
  +      rootNode.expand();
  +    }
       return TreeTable<TreemapNode>(
         dataRoots: [rootNode],
         columns: columns,
  
positive.code: 
    final TreemapNode rootNode;
  
    final TreeColumnData<TreemapNode> treeColumn;
    final ColumnData<TreemapNode> sortColumn;
    final List<ColumnData<TreemapNode>> columns;
  
negative.code: import '../utils.dart';
  
  class CodeSizeSnapshotTable extends StatelessWidget {
    factory CodeSizeSnapshotTable({@required rootNode, autoExpandRoot = true}) {
      final treeColumn = _NameColumn(currentRootLevel: rootNode.level);
      final sizeColumn = _SizeColumn();
      final columns = List<ColumnData<TreemapNode>>.unmodifiable([
  