In the com.graphisoft.AC 9.0.0 USA v1.plist preference file there's a key for WorkEnvironment/ShowContextMenuTabPage. Flip it to true and you can edit the context menus in Work Environment. I use a free utility called Pref Setter which is quite pleasant. You can quickly find keys Finder-style. I finally got the special menu turned on this way; I couldn't find it with both hands and a flashlight with the Apple dev tool.
This is a good time to say to everyone: If you don't know what I'm talking about, leave it alone. When editing things you're not supposed to edit, you can't complain if something breaks. Also back up your stuff, prefs and Work Environment. Be prepared to retreat if something goes haywire.