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)

addHTML(this, html, bbox);
  }
  [$getAvailableSpace]() {
    return getAvailableSpace(this);
  }
  [$toHTML](availableSpace) {
    if (
      this.presence === "hidden" ||
      this.presence === "inactive" ||
      this.h === 0 ||
      this.w === 0
    ) {
      return HTMLResult.EMPTY;
    }
    fixDimensions(this);
    const children = [];
    const attributes = {
      id: this[$uid],
      class: [],
    };
    setAccess(this, attributes.class);
    if (!this[$extra]) {
      this[$extra] = Object.create(null);
    }
    Object.assign(this[$extra], {
      children,
      attributes,
      attempt: 0,
      line: null,