diff --git a/Polyhedron/demo/Polyhedron/Scene_item.cpp b/Polyhedron/demo/Polyhedron/Scene_item.cpp
index cd1e4157e41..8e8e7b2a9ad 100644
--- a/Polyhedron/demo/Polyhedron/Scene_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_item.cpp
@@ -4,6 +4,11 @@ const QColor Scene_item::defaultColor = QColor(100, 100, 255);
 
 Scene_item::~Scene_item() {}
 
+void Scene_item::itemAboutToBeDestroyed(Scene_item* item) {
+  if(this == item)
+    emit aboutToBeDestroyed();
+}
+
 // Rendering mode as a human readable string
 QString Scene_item::renderingModeName() const
 {
diff --git a/Polyhedron/demo/Polyhedron/Scene_item.h b/Polyhedron/demo/Polyhedron/Scene_item.h
index a294e8edaa5..ac2b64f2192 100644
--- a/Polyhedron/demo/Polyhedron/Scene_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_item.h
@@ -76,6 +76,11 @@ public slots:
       rendering_mode = m; 
   }
 
+  virtual void itemAboutToBeDestroyed(Scene_item*);
+
+signals:
+  void aboutToBeDestroyed();
+
 protected:
   // The four basic properties
   QString name_;