Hi Tau,

the gtk backend does not comes loaded by default, you need to load it:

Metacello new
        repository: 'github://pharo-spec/Spec-Gtk';
        baseline: 'SpecGtk';
        onConflict: [ :e | e useIncoming ];
        onUpgrade: [ :e | e useIncoming ];
        load.   

and of course, remember you need gtk3 in your system :)
check here: https://github.com/pharo-spec/Spec-Gtk
cheers!
Esteban
On Jul 19 2021, at 12:15 am, jbn126859530.7 <tau@cedalion.info> wrote:
 
Hi.

I'm learning Spec 2.0 with the help of the book "Building user interface with Spec 2.0". In section 2.17 of the book, the authors make a subclass of SpGtkConfiguration. However, no such class exists, only a SpMorphicConfiguration. Moreover, if I do something like: "app useBackend: #Gtk", I get a NotFound error. Again, "app useBackend: #Morphic" work as intended. As Pharo 9 annonced the availability of a GTK backend, I would like to know how to access it.

Thanks.

tau.