Attach (recommended) or Link to PDF file here:
issue13500 (in test corpus)

This regressed when landing #13566. 

What is the expected behavior? (add screenshot)
<img width="664" alt="image" src="https://user-images.githubusercontent.com/942640/122467522-7bc8aa80-cf6f-11eb-9d4d-311eb7c64fb2.png">


What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/942640/122467565-85eaa900-cf6f-11eb-9c10-8a8686ed440c.png)


return this[$extra].availableSpace;
  }
  [$toHTML](availableSpace) {
    
    const style = toStyle(this, "position");
    const attributes = {
      style,
      id: this[$uid],
      class: ["xfaArea"],
    };
    if (isPrintOnly(this)) {
      attributes.class.push("xfaPrintOnly");
    }
    if (this.name) {
      attributes.xfaName = this.name;
    }
    const children = [];
    this[$extra] = {
      children,
      width: 0,
      height: 0,
      availableSpace,
    };
    const result = this[$childrenToHTML]({
      filter: new Set([
        "area",