diff --git a/js/extensionPrefs/main.js b/js/extensionPrefs/main.js
index d8c51bfa5..4125605b9 100644
--- a/js/extensionPrefs/main.js
+++ b/js/extensionPrefs/main.js
@@ -1,4 +1,7 @@
 /* exported main */
+imports.gi.versions.Gdk = '3.0';
+imports.gi.versions.Gtk = '3.0';
+
 const Gettext = imports.gettext;
 const { Gdk, GLib, Gio, GObject, Gtk, Pango } = imports.gi;
 const Format = imports.format;