diff --git a/examples/bwv846_prelude.rb b/examples/bwv846_prelude.rb
index 21a8803..f84c57e 100644
--- a/examples/bwv846_prelude.rb
+++ b/examples/bwv846_prelude.rb
@@ -15,7 +15,7 @@ def absolute pitch, duration
 		/(?<letter>[a-g][-+_]*)(?<octave>\d*)/ =~ pitch
 		octave = @@last_octave ||= '4' if octave.empty?
 		result = Alda::Note.new "o#{@@last_octave = octave} #{letter}", duration
-		@events.push result
+        @events.push result.tap { _1.parent = self }
 		result
 	end
 end
diff --git a/lib/alda-rb/version.rb b/lib/alda-rb/version.rb
index 8ee5452..eb5cc8a 100644
--- a/lib/alda-rb/version.rb
+++ b/lib/alda-rb/version.rb
@@ -7,5 +7,5 @@ module Alda
 	# The version number of alda-rb.
 	#
 	# The same as that in alda-rb gem spec.
-	VERSION = '0.2.0'
+	VERSION = '0.2.1'
 end