property OnFormFieldExit;
Fired when the form-fill engine loses focus on a form field.
Use to commit derived data, clear highlights, or validate the field value.
Wraps the corresponding PDFium API and exposes it as a TPdf instance member so consumers do not have to manage FPDF_DOCUMENT handles directly.
Pdf1.Active before calling page-scoped operations; methods that require an open document raise EPdfError otherwise.SaveToFile to persist.
procedure TForm1.PdfOnFormFieldExit(Sender: TObject);
begin
// react to OnFormFieldExit
end;