Why is my Diablo 2R HUD in the middle of the screen

The HUD control line (with the skills and health/mana orbs) are positioned almost in the middle of the screen, and it’s making it very hard to move and attack below the character.

https://www.dropbox.com/s/07lh968t0bppnw9/d2r-hud.jpg?dl=1

In Options, the display calibration shows the corners in the top and some 2/3 down, where the HUD is then placed.

Why is this happening, and what can I do about it?

I’m running in Windows 10 Home on a Bootcamp iMac.