How to fix "GLib-GIO-ERROR Settings schema 'org.gtk.Settings.FileChooser' is not installed"?

After updating my ubuntu 20.04 installation first inkscape "Save as" led to a crash of the program complaining about the FileChooser. While trying to fix the problem, now also nautilus . gives the same error:

org.gnome.Nautilus:5098): GLib-GIO-ERROR **: 21:48:41.547: Settings schema 'org.gtk.Settings.FileChooser' is not installed

Failed attempts to fix the issue:

1. Reinstalling gtk3 sudo apt-get reinstall gtk-3.0 followed by logout/login.

2. Installing gtk2 via sudo apt-get install gtk2.0 followed by logout/login.

Possibly related: broken-schema-org-gtk-settings-filechooser

This schema is contained in libgtk-3-common package. You have to reinstall it with

sudo apt-get update
sudo apt-get install --reinstall libgtk-3-common