left_plist.add (ARDOUR::Properties::start, left_start_offset);
left_plist.add (ARDOUR::Properties::length, left_length);
left_plist.add (ARDOUR::Properties::name, string ("xfade out"));
left_plist.add (ARDOUR::Properties::layer, 0);
left_plist.add (ARDOUR::Properties::fade_in_active, true);
left_plist.add (ARDOUR::Properties::start, left_start_offset);
left_plist.add (ARDOUR::Properties::length, left_length);
left_plist.add (ARDOUR::Properties::name, string ("xfade out"));
left_plist.add (ARDOUR::Properties::layer, 0);
left_plist.add (ARDOUR::Properties::fade_in_active, true);