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)

} else if (target instanceof ContentArea) {
            const index = contentAreas.findIndex(e => e === target);
            if (index !== -1) {
              i = index - 1;
            } else {
              targetPageArea = target[$getParent]();
              startIndex =
                targetPageArea.contentArea.children.findIndex(
                  e => e === target
                ) - 1;
            }
          }
          continue;
        }
        flush(i);
      }
      this[$extra].pageNumber += 1;
      if (targetPageArea) {
        if (targetPageArea[$isUsable]()) {
          targetPageArea[$extra].numberOfUse += 1;
        } else {
          targetPageArea = null;
        }
      }
      pageArea = targetPageArea || pageArea[$getNextPage]();
    }
  }
}
class Text extends ContentObject {
  constructor(attributes) {