This is a sensible addition. I’ve accepted it as a feature request rather than a bug because PopupMenu does not currently provide per-row enabled state.
The planned API is:
menu.SetRowEnabled(2, False)
Print(menu.RowEnabled(2))
Disabled rows will remain visible using the platform’s disabled appearance but will not be selectable. New rows will be enabled by default, separators will remain disabled, and the same API is planned for Desktop and Web projects.
Tracked here: https://feedback.objo.dev/feature/1486