Why would a Native AnimNotify not show up in the editor?

According to this post, creating a new class derived from UAnimNotify will show up in the menu in Persona when trying to add new animnotifies. I used the given example code in the post to add a new one (though I had to add implementations for Notify() and World() ).

Any reason why a new native AnimNotify would not show up in the editor? Thank you.

Unreal Engine 4.2 Update Preview - Unreal Engine=> New: Native Anim Notifies and states are now supported.

Notifies with the Abstract markup in their UCLASS macro won’t show up (as expected since they’re abstract), but blueprint child classes of that abstract class will also not show up (I don’t know why).