External References question

I'm trying to edit one of the components in an assembly, but a message pops up saying, "This part has features defined in the context of another assembly . . . . You can edit the part, but cannot create any external references to the components of the current assembly".

The assembly named in the message is one that was deleted long ago, so obviously I don't want a part to rely on anything from it. How can I find which features are the ones defined in the deleted assembly? If I find these features and delete them, will the message go away?

SolidworksParts And Features