@Override
  public @Nullable TextRange addCustomizations(@NotNull Editor editor, @Nullable String selectedKeyName) {
    boolean ourKey = DefaultLanguageHighlighterColors.DOC_COMMENT_GUIDE.getExternalName().equals(selectedKeyName) ||
                     DefaultLanguageHighlighterColors.DOC_COMMENT_LINK.getExternalName().equals(selectedKeyName);
    Document document = editor.getDocument();
    int offset = document.getText().indexOf("RENDERED DOC");
    int line = document.getLineNumber(offset);
    FoldingModel foldingModel = editor.getFoldingModel();
    CustomFoldRegion[] region = {null};
    foldingModel.runBatchFoldingOperation(() -> {
      region[0] = foldingModel.addCustomLinesFolding(line, line,
                                                     new CustomFoldRegionRendererWrapper(DocRenderItemImpl.createDemoRenderer(editor), ourKey));
    });
    return ourKey && region[0] != null ? region[0].getTextRange() : null;
  }
@Override
  public @Nullable TextRange addCustomizations(@NotNull Editor editor, @Nullable String selectedKeyName)