Can't Nest Areas/POIs

I created a large area (-10000,-10000×10000,10000) named Argoth for my world.

I then created an area called Briarflow Sound, an island in the NW corner of my map. Everything was fine until I went to select the Parent Area. As soon as I clicked on Parent Area, it immediately scrolled by screen back to the top of the area creation screen, would not allow me to select anything from the Parent Area dropdown.

If I click the auto button, however, it does properly update the Parent Area.

Behavior exists in Chrome and MS Edge.