property OnFormFieldFocusChange: TPdfFormFieldFocusEvent;
Događaj receives the new field index, or -1 when the focus cursor is cleared. It is raised by TPdfView focus navigation methods, not by TPdf methods
Use the event to update status text, synchronize a speech cursor, or select the corresponding FormFieldInfo entry
PdfView1.OnFormFieldFocusChange := PdfFormFieldFocusChange;
procedure TMainForm.PdfFormFieldFocusChange(Sender: TObject; FieldIndex: Integer);
begin
StatusBar1.SimpleText := IntToStr(FieldIndex);
end;