+ gain_slider->set_controllable (amp->gain_control());
+
+ if (!_route || _route->output()->n_ports().n_midi() == 0) {
+ _is_midi = false;
+ gain_adjustment.set_lower (0.0);
+ gain_adjustment.set_upper (1.0);
+ gain_adjustment.set_step_increment (0.01);
+ gain_adjustment.set_page_increment (0.1);
+ } else {
+ _is_midi = true;
+ gain_adjustment.set_lower (0.0);
+ gain_adjustment.set_upper (2.0);
+ gain_adjustment.set_step_increment (0.05);
+ gain_adjustment.set_page_increment (0.1);
+ }
+