You've probably turned on Hide Windows items on file context menus (shift overrides) in Preferences - Miscellaneous - Windows Integration.
The setting's name can be confusing. Instead of "Windows items", think "Non-Opus items".
If you hold shift when you right-click then you should see the menus.
If you want to hide some menu items but not others then you can leave the option turned on and selectively add back individual programs' menu items as described here: