FocusFormField метод

The form-focus members maintain a logical cursor over AcroForm widget annotations on the current page. The cursor follows FormFieldTabOrder and returns -1 when no current-page field is focused

Use these members when an application needs to walk fields from code, drive voice-assisted form filling, or expose the active field to an accessibility layer without relying on mouse hit testing

• API names, type names, and PDF terms keep their original spelling so code search remains reliable
• Call the member only after the owning document or viewer is active unless the syntax describes an event or design-time property