Attach (recommended) or Link to PDF file here:
http://education.ohio.gov/getattachment/Topics/Special-Education/Preschool-Special-Education/ETR-Preschool-Planning-Form.pdf.aspx

- Web browser and its version: Firefox 89.0.1
- Operating system and its version: Windows 10 10.0.19043.1052
- PDF.js version: commit 5d251a3a3e7bfaa8fbfa07f0b7f9901eb3f999d9
- Is a browser extension: No

Steps to reproduce the problem:
1. Enable XFA support
2. Open form

What is the expected behavior? (add screenshot)
Shapes stay inside table cells
![image](https://user-images.githubusercontent.com/7104454/122572782-1252a580-d01c-11eb-9d0f-5fed46d6f2fe.png)

What went wrong? (add screenshot)
Shapes fall outside cells (among other issues)
![image](https://user-images.githubusercontent.com/7104454/122572885-2d251a00-d01c-11eb-8863-fa3b9969f0ea.png)

_setValue(this, value);
  }
  [$getExtra](availableSpace) {
    if (!this[$extra]) {
      let { width, height } = availableSpace;
      switch (this.placement) {
        case "left":
        case "right":
        case "inline":
          width = this.reserve <= 0 ? width : this.reserve;
          break;
        case "top":
        case "bottom":
          height = this.reserve <= 0 ? height : this.reserve;
          break;
      }
      this[$extra] = layoutNode(this, { width, height });
    }
    return this[$extra];
  }
  [$toHTML](availableSpace) {