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)

node[$extra].target = target;
      return true;
    }
    return false;
  }
  if (!(target instanceof ContentArea)) {
    target = null;
  }
  const pageArea = target && target[$getParent]();
  let index;
  if (node.startNew) {
    if (target) {
      const contentAreas = pageArea.contentArea.children;
      index = contentAreas.findIndex(e => e === target) - 1;
    } else {
      index = currentPageArea.contentArea.children.findIndex(
        e => e === currentContentArea
      );
    }
  } else if (target && target !== currentContentArea) {
    const contentAreas = pageArea.contentArea.children;
    index = contentAreas.findIndex(e => e === target) - 1;
  } else {
    return false;
  }
  node[$extra].target = pageArea === currentPageArea ? null : pageArea;
  node[$extra].index = index;
  return true;
}
function handleOverflow(node, extraNode, space) {