Hi,

When starting gnome-tweak-tool, it prints a warning

    GLib-GIO-Message: Using the 'memory' GSettings backend.  Your settings will not be saved or shared with other applications.

The patch below has gnome-tweak-tool communicate with gsettings instead
of using the `memory.  I'm not sending it as a fix yet because 
gnome-tweak-tool does not list any themes, as davexunit reported.

I'm attaching the log that I get when building it, there's a warning
about xml files not being written and collisions, could that be the
cause of missing themes?

Greetings, Jan

diff --git a/gnu/packages/gnome.scm b/gnu/packages/gnome.scm
index 8384c76..c9463e8 100644
--- a/gnu/packages/gnome.scm
+++ b/gnu/packages/gnome.scm
@@ -5170,7 +5170,8 @@ desktop.  It supports multiple calendars, monthly view and yearly view.")
      `(("python" ,python-2)
        ("python2-pygobject" ,python2-pygobject)))
     (propagated-inputs
-     `(("libnotify" ,libnotify)
+     `(("dconf" ,dconf)
+       ("libnotify" ,libnotify)
        ("gobject-introspection" ,gobject-introspection)
        ("gsettings-desktop-schemas" ,gsettings-desktop-schemas)
        ("gtk+" ,gtk+)))