specialFormSelectItemText method
The form text form of selection's label, if any.
Implementation
String? specialFormSelectItemText(Selection selection, String? form) {
final sel = selection.index == -1
? question.attachChoice(selection)
: selection;
final tid = sel.choice!.textId;
if (tid == null || tid.isEmpty) return null;
return substituteStringArgs(itext(tid, form));
}