diff --git a/AABB_tree/demo/AABB_tree/MainWindow.cpp b/AABB_tree/demo/AABB_tree/MainWindow.cpp
index 4321e396b8d..cd1444b9968 100644
--- a/AABB_tree/demo/AABB_tree/MainWindow.cpp
+++ b/AABB_tree/demo/AABB_tree/MainWindow.cpp
@@ -16,7 +16,7 @@
 
 
 MainWindow::MainWindow(QWidget* parent)
-  : CGAL::Qt::DemosMainWindow(parent), myEngine(new QJSEngine())
+  : CGAL::Qt::DemosMainWindow(parent), myEngine(new QJSEngine(this))
 {
   ui = new Ui::MainWindow;
   ui->setupUi(this);
diff --git a/AABB_tree/demo/AABB_tree/MainWindow.h b/AABB_tree/demo/AABB_tree/MainWindow.h
index 50cd927a7cb..87f6de0c76c 100644
--- a/AABB_tree/demo/AABB_tree/MainWindow.h
+++ b/AABB_tree/demo/AABB_tree/MainWindow.h
@@ -23,7 +23,7 @@ public:
   QJSEngine* myEngine;
 
   Foo()
-    : myEngine(new QJSEngine())
+    : myEngine(new QJSEngine(this))
   {
       QJSValue baz = myEngine->newQObject(this);
       myEngine->.globalObject().setProperty("baz", baz);