crossfade_changed (all_crossfade_properties);
crossfade->PropertyChanged.connect (*this, invalidator (*this), ui_bind (&CrossfadeView::crossfade_changed, this, _1), gui_context());
crossfade_changed (all_crossfade_properties);
crossfade->PropertyChanged.connect (*this, invalidator (*this), ui_bind (&CrossfadeView::crossfade_changed, this, _1), gui_context());