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)


const parent = this[$getParent]();
    const style = Object.create(null);
    let propName = "color";
    if (parent instanceof Border) {
      propName = "background";
    }
    if (parent instanceof Rectangle || parent instanceof Arc) {
      propName = "fill";
      style.fill = "transparent";
    }
    for (const name of Object.getOwnPropertyNames(this)) {
      if (name === "extras" || name === "color") {
        continue;
      }
      const obj = this[name];
      if (!(obj instanceof XFAObject)) {
        continue;
      }
      style[propName] = obj[$toStyle](this.color);
      return style;
    }
    if (this.color) {
      style[propName] = this.color[$toStyle]();
    }
    return style;
  }
}
class Filter extends XFAObject {