Attach (recommended) or Link to PDF file here:
See pdf in https://github.com/mozilla/pdf.js/issues/3109

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Windows 10
- PDF.js version: builtin viewer

Steps to reproduce the problem:
1. Look at outlines

What is the expected behavior? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/141514798-0e656865-1cbf-4fb8-a89b-530d36da23c9.png)

What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/5641725/141514740-c95e0237-8bf4-4129-a4a5-cb2ea5a3f4df.png)

this._lastToggleIsShow = show;
    for (const toggler of root.querySelectorAll(".treeItemToggler")) {
      toggler.classList.toggle("treeItemsHidden", !show);
    }
  }
  /**
   * Collapse or expand all subtrees of the `container`.
   * @private
   */
  _toggleAllTreeItems() {
    this._toggleTreeItem(this.container, !this._lastToggleIsShow);
  }
  /**
   * @private
   */
  _finishRendering(fragment, count, hasAnyNesting = false) {