diff --git a/libs/evoral/src/Event.cpp b/libs/evoral/src/Event.cpp
index 783634f..c3bbbd0 100644
--- a/libs/evoral/src/Event.cpp
+++ b/libs/evoral/src/Event.cpp
@@ -17,6 +17,7 @@
  */
 
 #include <glib.h>
+#include <iostream>
 #include "evoral/Event.hpp"
 
 namespace Evoral {
@@ -73,6 +74,7 @@ Event<Timestamp>::Event(const Event& copy, bool owns_buf)
 	, _owns_buf(owns_buf)
         , _id (copy.id())
 {
+	std::cout << "Event copy constructor: owns_buf=" << owns_buf << ", copy._buf=" << copy._buf << "\n";
 	if (owns_buf) {
 		_buf = (uint8_t*)malloc(_size);
 		if (copy._buf) {