diff --git a/gtk2_ardour/mixer_strip.cc b/gtk2_ardour/mixer_strip.cc
index aba5800385..c2e38a1d34 100644
--- a/gtk2_ardour/mixer_strip.cc
+++ b/gtk2_ardour/mixer_strip.cc
@@ -314,6 +314,7 @@ MixerStrip::~MixerStrip ()
 
 	delete input_selector;
 	delete output_selector;
+	delete comment_window;
 }
 
 void