Currently working

gistfile1.pl

class My::Model {
    use GTKBind::Model;

    attach 'text' => (
        to      => [ 'entry', 'label' ],
        default => 'derp',
    );

    attach 'reset_active' => (
        to      => { id => 'resetbutton', property => 'sensitive' },
        default => 0,

        depends   => 'text',
        calculate => sub {
            my $self = shift;
            my $val  = shift;    #In this case, it's always 'text'.
            return $self->$val ne $self->default($val);
        }
    );

}


class My::Controller {
    use GTKBind::Controller;
    on 'resetbutton', 'clicked' => sub {
        my $self = shift;
        $self->model->reset('text');
    };

    watch 'reset_active' => sub {
        say "reset_active changed";
    };
}