diff --git a/Polyhedron/demo/Polyhedron/Polyhedron_demo_point_set_smoothing_plugin.cpp b/Polyhedron/demo/Polyhedron/Polyhedron_demo_point_set_smoothing_plugin.cpp
index 5b131aed60b..3667d8be1a4 100644
--- a/Polyhedron/demo/Polyhedron/Polyhedron_demo_point_set_smoothing_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Polyhedron_demo_point_set_smoothing_plugin.cpp
@@ -75,6 +75,9 @@ void Polyhedron_demo_point_set_smoothing_plugin::on_actionJetSmoothing_triggered
 
     points->invalidate_bounds();
 
+    // calling jet_smooth_point_set breaks the normals
+    item->set_has_normals(false);
+
     // update scene
     scene->itemChanged(index);