XMLNode &before = alist->get_state();
if (!rv.audio_region()->envelope_active()) {
XMLNode ®ion_before = rv.audio_region()->get_state();
rv.audio_region()->set_envelope_active(true);
XMLNode ®ion_after = rv.audio_region()->get_state();
XMLNode &before = alist->get_state();
if (!rv.audio_region()->envelope_active()) {
XMLNode ®ion_before = rv.audio_region()->get_state();
rv.audio_region()->set_envelope_active(true);
XMLNode ®ion_after = rv.audio_region()->get_state();