Attach (recommended) or Link to PDF file here:
https://www.canada.ca/content/dam/ircc/migration/ircc/english/pdf/kits/forms/eimm5669e.pdf
[eimm5669e.pdf](https://github.com/mozilla/pdf.js/files/7225677/eimm5669e.2.pdf)

Configuration:
- Web browser and its version: Firefox nightly
- Operating system and its version: Linux Debian

Steps to reproduce the problem:
1. Look at the bottom of page 2

const style = toStyle(this, "border", "margin");
    const ui = this[$getParent]();
    const field = ui[$getParent]();
    const fontSize = (field.font && field.font.size) || 10;
    const optionStyle = {
      fontSize: `calc(${fontSize}px * var(--zoom-factor))`,
    };
    const children = [];
    if (field.items.children.length > 0) {
      const items = field.items;
      let displayedIndex = 0;