[FreeBSD UNIX] desktop background settings not set

In XFCE 4.20 FreeBSD UNIX 14.2, I can't set desktop settings such as background/gradient. You can see below I selected a different image, but set image to 'none' and replaced it with gradient, none which was applied. This seems to happen on ThinkPads with Intel graphics but maybe not desktops with AMD or Nvidia (though I don't use FreeBSD as much there and should retest). They all also use Slackware GNU/Linux (shared /home) which doesn't have this problem. In FreeBSD opening desktop settings it says 'unable to load images from folder "null": operation was cancelled'.