internal void ExpandFields(PdfFormField field, List<PdfAnnotation> allAnnots)
{
allAnnots.Add(field);
List<PdfFormField> kids = field.Kids;
if (kids != null) {
for (int k = 0; k < kids.Count; ++k) {
ExpandFields((PdfFormField)kids[k], allAnnots);
}
}
}