Comment 8 for bug 1599453

Oops...I wasn't done with that comment but I don't see a way to edit it.

I put that code after `self.set_visual(visual)` on line 377. However, I'm not entirely sure if that's the best place to put it.

The other problem is I found this documentation, which says that override_background_color is deprecated as of 3.16, so it's really only a temporary solution. It says instead to override the background using CSS. Is there anywhere currently using CSS in this code? I haven't found a good place to put that yet.

https://lazka.github.io/pgi-docs/#Gtk-3.0/classes/Widget.html#Gtk.Widget.override_background_color