diff --git a/Polyhedron/demo/Polyhedron/Plugins/PMP/Engrave_text_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PMP/Engrave_text_plugin.cpp
index 1b18fade896..c45bfdc619e 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PMP/Engrave_text_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PMP/Engrave_text_plugin.cpp
@@ -961,8 +961,8 @@ private:
   int pointsize;
   bool locked;
   EPICK::Line_2 bf_line;
-  QGraphicsScene *graphics_scene;
-  Navigation* navigation;
+  QGraphicsScene *graphics_scene = nullptr;
+  Navigation* navigation = nullptr;
 };
 #include "Engrave_text_plugin.moc"
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PMP/Mean_curvature_flow_skeleton_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PMP/Mean_curvature_flow_skeleton_plugin.cpp
index be6a1ac02e8..9f959f673bb 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PMP/Mean_curvature_flow_skeleton_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PMP/Mean_curvature_flow_skeleton_plugin.cpp
@@ -321,8 +321,8 @@ public Q_SLOTS:
 private:
   Scene_mcf_item *getMCFItem();
   void createContractedItem(Scene_mcf_item* item);
-  QDockWidget* dockWidget;
-  Ui::Mean_curvature_flow_skeleton_plugin* ui;
+  QDockWidget* dockWidget = nullptr;
+  Ui::Mean_curvature_flow_skeleton_plugin* ui = nullptr;
 
 }; // end Polyhedron_demo_mean_curvature_flow_skeleton_plugin
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
index 448c9b27027..fffd332a832 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
@@ -493,14 +493,14 @@ protected:
   void parameterize(Parameterization_method method);
 
 private:
-  Messages_interface *messages;
+  Messages_interface *messages = nullptr;
   QList<QAction*> _actions;
-  QDockWidget* dock_widget;
+  QDockWidget* dock_widget = nullptr;
   Ui::Parameterization ui_widget;
   QGraphicsScene *graphics_scene;
-  Navigation* navigation;
+  Navigation* navigation = nullptr;
   QMap<Scene_item*, UVItem*> projections;
-  UVItem* current_uv_item;
+  UVItem* current_uv_item = nullptr;
 }; // end Polyhedron_demo_parameterization_plugin
 
 void Polyhedron_demo_parameterization_plugin::on_prevButton_pressed()
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh_deformation/Edit_polyhedron_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh_deformation/Edit_polyhedron_plugin.cpp
index fb14c181c48..13c597b5d3b 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh_deformation/Edit_polyhedron_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh_deformation/Edit_polyhedron_plugin.cpp
@@ -79,11 +79,11 @@ private:
   void updateSelectionItems(Scene_facegraph_item* target);
 
   Ui::DeformMesh ui_widget;
-  QDockWidget* dock_widget;
+  QDockWidget* dock_widget = nullptr;
 
-  QAction* actionDeformation;
+  QAction* actionDeformation = nullptr;
   RenderingMode last_RM;
-  QShortcut* e_shortcut;
+  QShortcut* e_shortcut = nullptr;
 }; // end Polyhedron_demo_edit_polyhedron_plugin
 
 QList<QAction*> Polyhedron_demo_edit_polyhedron_plugin::actions() const {