There is a known problem importing the Gtk library from seed on systems where seed is built against Gtk2, if Gtk3 is also installed; this is because both Gtk versions install gobject-introspection typelib files in the repository, and unless the desired version is explicitly specified. Simply importing Gtk fails as such: > imports.gi.Gtk seed: symbol lookup error: /usr/lib64/libgtk-x11-3.0.so.0: undefined symbol: g_application_get_type The workaround is to specify the version as such: > // note the quotes; otherwise 2.0 gets evaluated as just 2 > imports.gi.versions.Gtk = "2.0"; 2.0 > Gtk = imports.gi.Gtk; [object Object] > See example 3 on the Reference Manual's Importer section: http://library.gnome.org/devel/seed/stable/seed-importer.html