I'm afraid, my darlings, everyone might be overcomplicating a simple thing (that is, if we're talking about only preview): look at the bottom of your preview window. :D

First option is Port Setup, second is Display Tracking, third is Display Shadows - aka the one you want.

In order, with Andy the dummy on screen, what they look like:

I can't see for sure from your screenshot if that's the issue and you have "No Shadows" selected, but if you don't, I'd select something else and then the option you want, maybe that will wake Poser up. Sometimes it's finicky.

- - - - - - 

Feel free to call me Ohki!

Poser Pro 11, Poser 12 and Poser 13, Windows 10, Superfly junkie. My units are milimeters.

Persephone (the computer): AMD Ryzen 9 5900x, RTX 3070 GPU, 96gb ram.