diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
index 6fe8a326238..55c89a917ef 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
@@ -1119,6 +1119,10 @@ void Scene_polyhedron_item::update_halfedge_indices()
         hit->id()=id++;
     }
 }
+void Scene_polyhedron_item::invalidate_aabb_tree()
+{
+  delete_aabb_tree(this);
+}
 
 #include "Scene_polyhedron_item.moc"
 
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
index 8b9e6c8f8b0..2af47fa6c28 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.h
@@ -81,6 +81,7 @@ public Q_SLOTS:
     void update_vertex_indices();
     void update_facet_indices();
     void update_halfedge_indices();
+    void invalidate_aabb_tree();
 
 Q_SIGNALS:
     void selected_vertex(void*);