Blank page when running on X11 (but Wayland is ok)

For some reason I am getting a white screen when I run my app under Xfce. It seems to have laid out the page and I am getting mouse-over effects. It is as if everything id rendered as white on white.

When I switch to Gnome Classic, everything is fine (except Gnome has some problems of its own, so I want to use Xfce).

Any ideas about fixes, work arounds, diagnostics?

I am using current versions of everything:

* Linux fedora 6.5.11-300.fc39.x86_64
* XFCE 4.18
* GTK 3.24.38
* web-view = "0.7.3"

I get log messages for some reason of
```
LOG version: 5.0 (X11; Linux x86_64) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.4 Safari/605.1.15
LOG user agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.4 Safari/605.1.15
```

*Edit:* Actually, the problem seems to occur in X11 (whether Xfce or Gnome) but not on Wayland (Gnome only, does not run XFCE).