WordPress comment box disappears when I activate this plugin

FYI, I have tried deactivating all the plugins except this one, and switching to the default theme to see if there was any conflict, but the WordPress comments still do not show up if this plugin is activated.

The Facebook Comments Box social plugin replaces the WordPress comments form. Visitors are only encouraged to author new comments in one place.

Hmm, I’ve seen it on other sites where there are both, and in fact there used to be both on my site. I have no idea when it changed.
Here’s one site where there are both.
https://erintillotson.com/2-easy-ways-to-create-facebook-images-in-minutes

You can customize your site to have both comment form for WordPress comments and a Comments Box comment area through filters and actions.

The default behavior of the Comments Box social plugin integration offered in the Facebook plugin for WordPress is a replacement of your theme’s comments template.

Is it possible to have an option to continue showing the wordpress comments, perhaps as a tabbed comments section? For example, one tab has the existing facebook comments box and the other tab has the wordpress comments. And have the number of comments be a combination of the two… I have comments on my pre-facebook-plugin posts that are now no longer showing up, and show as having 0 comments.