Split-screen players: Has anyone figured out how to merge the screens when close to each other?

This was a popular couch co-op feature in Divinity 1 and 2, so I’m sure they intend for it to be included here too. I just can’t figure out how to do it.

In DOS1 and DOS2, any time your two characters were close to each other, it would dynamically merge the split screen into one fullscreen, which was super convenient. Has anyone been able to figure this out?

I see a couple of steam community posts where people have run into the same issue, even though they see that it exists in settings. Is it possibly bugged?