how to draw a border around all kinds of input fields?

[manuschillerdev]

I use pdf-lib to test a pdf if its name attributes match the name attributes of a json object.

export function highlightErrorsInPDF(pdf: PDFDocument, fieldNames: Map<string, undefined>) {
  for (const field of pdf.getForm().getFields()) {
    if (!fieldNames.has(field.getName())) continue;

    if (field instanceof PDFTextField) {
      field.setText("attention");
    } 

    const [widget] = field.acroField.getWidgets();
    const ac = widget.getAppearanceCharacteristics();
    ac?.setBackgroundColor(colorToComponents(rgb(0, 1, 0)));

    widget.getBorderStyle()?.setWidth(2);
    ac?.setBorderColor(colorToComponents(rgb(1, 0, 0)));
  }

  return pdf;
}

this works well for TextFields with values, but:
as soon as I do not fill the Field with some dummy text (if I comment of line 6 field.setText("attention");) the border does not get drawn.

Also the border does not get drawn for field types other than TextFields.

Unfortunately I don't have any idea how to debug this any further, so any help is much appreciated! :)