FormCanRedo method

FormCanRedo wraps PDFium's FORM_CanRedo. It returns True when the FOCUSED AcroForm widget has at least one undone edit in its redo stack that FormRedo could re-apply and False otherwise

Returns False safely when the view is inactive, the document has no AcroForm or no widget is focused

Making a fresh edit (typing, paste, etc.) clears the redo stack — FormCanRedo flips to False after the next edit This matches the standard text-editor convention

• FormCanRedo is the natural Enabled-state expression for a Redo menu item, toolbar button or context-menu entry
• Like FormCanUndo, FormCanRedo is per-widget — the answer changes as focus moves between widgets
• The probe is cheap — no document mutation, no JavaScript fire