diff --git a/Polyhedron/demo/Polyhedron/MainWindow.cpp b/Polyhedron/demo/Polyhedron/MainWindow.cpp
index 07d1880da35..54cfde41e68 100644
--- a/Polyhedron/demo/Polyhedron/MainWindow.cpp
+++ b/Polyhedron/demo/Polyhedron/MainWindow.cpp
@@ -151,6 +151,9 @@ MainWindow::MainWindow(QWidget* parent)
     QShortcut* shortcut = new QShortcut(QKeySequence(Qt::ALT+Qt::Key_Q), this);
     connect(shortcut, SIGNAL(activated()),
             this, SLOT(setFocusToQuickSearch()));
+    shortcut = new QShortcut(QKeySequence(Qt::Key_F5), this);
+    connect(shortcut, SIGNAL(activated()),
+            this, SLOT(reloadItem()));
   }
 
   proxyModel = new QSortFilterProxyModel(this);
@@ -888,44 +891,36 @@ void MainWindow::updateViewerBBox(bool recenter = true)
 }
 
 void MainWindow::reloadItem() {
-  QAction* sender_action = qobject_cast<QAction*>(sender());
-  if(!sender_action) return;
 
-  Scene_item* item = (Scene_item*)sender_action->data().value<void*>();
-  if(!item) {
-    std::cerr << "Cannot reload item: "
-              << "the reload action has not item attached\n";
-    return;
+  Scene_item* item = NULL;
+
+  Q_FOREACH(Scene::Item_id id, scene->selectionIndices())
+  {
+    item = scene->item(id);
+    QString filename = item->property("source filename").toString();
+    QString loader_name = item->property("loader_name").toString();
+    if(filename.isEmpty() || loader_name.isEmpty()) {
+       this->warning(QString("Cannot reload item %1: "
+                "the item has no \"source filename\" or no \"loader_name\" attached\n").arg(item->name()));
+      continue;
+    }
+
+    CGAL::Three::Polyhedron_demo_io_plugin_interface* fileloader = findLoader(loader_name);
+    QFileInfo fileinfo(filename);
+
+    CGAL::Three::Scene_item* new_item = loadItem(fileinfo, fileloader);
+
+    new_item->setName(item->name());
+    new_item->setColor(item->color());
+    new_item->setRenderingMode(item->renderingMode());
+    new_item->setVisible(item->visible());
+    Scene_item_with_properties *property_item = dynamic_cast<Scene_item_with_properties*>(new_item);
+    if(property_item)
+      property_item->copyProperties(item);
+    scene->replaceItem(scene->item_id(item), new_item, true);
+    new_item->invalidateOpenGLBuffers();
+    item->deleteLater();
   }
-  if(!item) {
-    std::cerr << "Cannot reload item: "
-              << "the reload action has a QObject* pointer attached\n"
-              << "that is not a Scene_item*\n";
-    return;
-  }
-  QString filename = item->property("source filename").toString();
-  QString loader_name = item->property("loader_name").toString();
-  if(filename.isEmpty() || loader_name.isEmpty()) {
-    std::cerr << "Cannot reload item: "
-              << "the item has no \"source filename\" or no \"loader_name\" attached\n";
-    return;
-  }
-
-  CGAL::Three::Polyhedron_demo_io_plugin_interface* fileloader = findLoader(loader_name);
-  QFileInfo fileinfo(filename);
-
-  CGAL::Three::Scene_item* new_item = loadItem(fileinfo, fileloader);
-
-  new_item->setName(item->name());
-  new_item->setColor(item->color());
-  new_item->setRenderingMode(item->renderingMode());
-  new_item->setVisible(item->visible());
-  Scene_item_with_properties *property_item = dynamic_cast<Scene_item_with_properties*>(new_item);
-  if(property_item)
-    property_item->copyProperties(item);
-  scene->replaceItem(scene->item_id(item), new_item, true);
-  new_item->invalidateOpenGLBuffers();
-  item->deleteLater();
 }
 
 CGAL::Three::Polyhedron_demo_io_plugin_interface* MainWindow::findLoader(const QString& loader_name) const {
@@ -1280,7 +1275,7 @@ void MainWindow::showSceneContextMenu(int selectedItemIndex,
       menu->addSeparator();
       if(!item->property("source filename").toString().isEmpty()) {
         QAction* reload = menu->addAction(tr("&Reload Item from File"));
-        reload->setData(qVariantFromValue((void*)item));
+        reload->setProperty("is_groupable", true);
         connect(reload, SIGNAL(triggered()),
                 this, SLOT(reloadItem()));
       }
@@ -1304,8 +1299,8 @@ void MainWindow::showSceneContextMenu(int selectedItemIndex,
 void MainWindow::showSceneContextMenu(const QPoint& p) {
   QWidget* sender = qobject_cast<QWidget*>(this->sender());
   if(!sender) return;
+  int main_index = scene->selectionIndices().first();
 
-  int index = -1;
   if(sender == sceneView) {
       QModelIndex modelIndex = sceneView->indexAt(p);
       if(!modelIndex.isValid())
@@ -1323,17 +1318,48 @@ void MainWindow::showSceneContextMenu(const QPoint& p) {
               menu->exec(sender->mapToGlobal(p));
           return;
       }
-      else
+      else if(scene->selectionIndices().size() > 1 )
       {
-          index = scene->getIdFromModelIndex(proxyModel->mapToSource(modelIndex));
-          scene->setSelectedItemIndex(index);
+        QMap<QString, QAction*> menu_actions;
+        Q_FOREACH(QAction* action, scene->item(main_index)->contextMenu()->actions())
+        {
+          if(action->property("is_groupable").toBool())
+            menu_actions[action->text()] = action;
+        }
+        Q_FOREACH(Scene::Item_id index, scene->selectionIndices())
+        {
+          if(index == main_index)
+            continue;
+
+          CGAL::Three::Scene_item* item = scene->item(index);
+          if(!item)
+            continue;
+          QVector<QString> action_names;
+          Q_FOREACH(QAction* action, item->contextMenu()->actions())
+          {
+            action_names.push_back(action->text());
+          }
+        }
+        QMenu menu;
+        Q_FOREACH(QString name, menu_actions.keys())
+        {
+          QAction* action = menu.addAction(name);
+          connect(action, &QAction::triggered, this, &MainWindow::propagate_action);
+        }
+
+          QAction* reload = menu.addAction(tr("&Reload Item from File"));
+          reload->setProperty("is_groupable", true);
+          connect(reload, SIGNAL(triggered()),
+                  this, SLOT(reloadItem()));
+        QAction* saveas = menu.addAction(tr("&Save as..."));
+        connect(saveas,  SIGNAL(triggered()),
+                this, SLOT(on_actionSaveAs_triggered()));
+        menu.exec(sender->mapToGlobal(p));
+        return;
       }
   }
-  else {
-    index = scene->mainSelectionIndex();
-  }
-
-  showSceneContextMenu(index, sender->mapToGlobal(p));
+  showSceneContextMenu(main_index, sender->mapToGlobal(p));
+  return;
 }
 
 void MainWindow::removeManipulatedFrame(CGAL::Three::Scene_item* item)
@@ -1547,56 +1573,68 @@ void MainWindow::on_actionLoad_triggered()
 void MainWindow::on_actionSaveAs_triggered()
 {
   Scene_item* item = NULL;
-  QAction* sender_action = qobject_cast<QAction*>(sender());
-  if(sender_action && !sender_action->data().isNull()) {
-    item = (Scene_item*)sender_action->data().value<void*>();
-  }
 
-  if(!item)
+  Q_FOREACH(Scene::Item_id id, scene->selectionIndices())
   {
-    item = scene->item(scene->mainSelectionIndex());
-  }
-  if(!item)
-    return;
-
-  QVector<CGAL::Three::Polyhedron_demo_io_plugin_interface*> canSavePlugins;
-  QStringList filters;
-  Q_FOREACH(CGAL::Three::Polyhedron_demo_io_plugin_interface* plugin, io_plugins) {
-    if(plugin->canSave(item)) {
-      canSavePlugins << plugin;
-      filters += plugin->saveNameFilters();
+    item = scene->item(id);
+    QVector<CGAL::Three::Polyhedron_demo_io_plugin_interface*> canSavePlugins;
+    QStringList filters;
+    Q_FOREACH(CGAL::Three::Polyhedron_demo_io_plugin_interface* plugin, io_plugins) {
+      if(plugin->canSave(item)) {
+        canSavePlugins << plugin;
+        filters += plugin->saveNameFilters();
+      }
     }
-  }
-  QString ext;
-  if(!filters.isEmpty())
-  {
+    QString ext1, ext2;
     QRegExp extensions("\\(\\*\\..+\\)");
-    extensions.indexIn(filters.first().split(";;").first());
-    ext = extensions.cap();
+    QStringList filter_ext;
+    Q_FOREACH(QString s, filters.first().split(";;"))
+    {
+      int pos = extensions.indexIn(s);
+      if( pos >-1)
+        filter_ext.append(extensions.capturedTexts());
+    }
     filters << tr("All files (*)");
-  }
-  if(canSavePlugins.isEmpty()) {
-    QMessageBox::warning(this,
-                         tr("Cannot save"),
-                         tr("The selected object %1 cannot be saved.")
-                         .arg(item->name()));
-    return;
-  }
-  QString caption = tr("Save %1 to File...%2").arg(item->name()).arg(ext);
-  //remove `)`
-  ext.chop(1);
-  //remove `(*.`
-  ext = ext.right(ext.size()-3);
-  QString filename =
-    QFileDialog::getSaveFileName(this,
-                                 caption,
-                                 QString("%1.%2").arg(item->name()).arg(ext),
-                                 filters.join(";;"));
-  if(filename.isEmpty())
-    return;
+    if(canSavePlugins.isEmpty()) {
+      QMessageBox::warning(this,
+                           tr("Cannot save"),
+                           tr("The selected object %1 cannot be saved.")
+                           .arg(item->name()));
+      continue;
+    }
+    QString caption = tr("Save %1 to File...").arg(item->name());
+    QString sf;
+    QString filename =
+        QFileDialog::getSaveFileName(this,
+                                     caption,
+                                     QString("%1").arg(item->name()),
+                                     filters.join(";;"),
+                                     &sf);
+    extensions.indexIn(sf.split(";;").first());
+    ext1 = extensions.cap();
+    //remove `)`
+    ext1.chop(1);
+    //remove `(*`
+    ext1 = ext1.right(ext1.size()-2);
+    if(filename.isEmpty())
+      continue;
 
-  viewer->update();
-  save(filename, item);
+    ext2 = filename.split(".").last();
+    QStringList final_extensions;
+    Q_FOREACH(QString s, filter_ext)
+    {
+      //remove `)`
+      s.chop(1);
+      //remove `(*.`
+      final_extensions.append(s.right(s.size()-3));
+    }
+    if(!final_extensions.contains(ext2))
+    {
+      filename = filename.append(ext1);
+    }
+    viewer->update();
+    save(filename, item);
+  }
 }
 
 void MainWindow::save(QString filename, CGAL::Three::Scene_item* item) {
@@ -2118,3 +2156,22 @@ void MainWindow::exportStatistics()
   outStream << str;
   output.close();
 }
+
+void MainWindow::propagate_action()
+{
+  QAction* sender = qobject_cast<QAction*>(this->sender());
+  if(!sender) return;
+  QString name = sender->text();
+  Q_FOREACH(Scene::Item_id id, scene->selectionIndices())
+  {
+    Scene_item* item = scene->item(id);
+    Q_FOREACH(QAction* action, item->contextMenu()->actions())
+    {
+      if(action->text() == name)
+      {
+        action->trigger();
+        break;
+      }
+    }
+  }
+}
diff --git a/Polyhedron/demo/Polyhedron/MainWindow.h b/Polyhedron/demo/Polyhedron/MainWindow.h
index cb91014cc56..dbf92ec601f 100644
--- a/Polyhedron/demo/Polyhedron/MainWindow.h
+++ b/Polyhedron/demo/Polyhedron/MainWindow.h
@@ -354,6 +354,8 @@ protected Q_SLOTS:
   void on_actionRecenterScene_triggered();
   //!Resizes the header of the scene view
   void resetHeader();
+  //!apply an action named `name` to all selected items
+  void propagate_action();
 protected:
   QList<QAction*> createSubMenus(QList<QAction*>);
   /*! For each objects in the Geometric Objects view, loads the associated plugins.
diff --git a/Polyhedron/demo/Polyhedron/Plugins/IO/OFF_io_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/IO/OFF_io_plugin.cpp
index e112da19b4c..54a111dbb88 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/IO/OFF_io_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/IO/OFF_io_plugin.cpp
@@ -146,6 +146,7 @@ Polyhedron_demo_off_plugin::load_obj(QFileInfo fileinfo) {
                                       std::move(faces),
                                       *(poly_item->polyhedron()));
     item = poly_item;
+    item->invalidateOpenGLBuffers();
   } else {
     Scene_polygon_soup_item* polygon_soup_item = new Scene_polygon_soup_item();
     polygon_soup_item->load(std::move(points), std::move(faces));
diff --git a/Polyhedron/demo/Polyhedron/Plugins/IO/Surface_mesh_io_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/IO/Surface_mesh_io_plugin.cpp
index a4961ed2855..52561c7a577 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/IO/Surface_mesh_io_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/IO/Surface_mesh_io_plugin.cpp
@@ -5,6 +5,8 @@
 #include <QObject>
 #include <QAction>
 #include <QMainWindow>
+#include <QMessageBox>
+#include <QApplication>
 #include <QDebug>
 #include "Scene_surface_mesh_item.h"
 #include "Scene_polygon_soup_item.h"
@@ -35,7 +37,9 @@ public:
      return QList<QAction*>();
    }
    QString name() const { return "surface_mesh_io_plugin"; }
-   QString nameFilters() const { return "OFF files to Surface_mesh (*.off);;Wavefront Surface_mesh OBJ (*.obj)"; }
+   QString loadNameFilters() const { return "OFF files to Surface_mesh (*.off);;Wavefront Surface_mesh OBJ (*.obj)"; }
+   QString saveNameFilters() const { return "OFF files (*.off);;Wavefront OBJ (*.obj)"; }
+   QString nameFilters() const { return QString(); }
    bool canLoad() const { return true; }
    CGAL::Three::Scene_item* load(QFileInfo fileinfo) {
      if(fileinfo.suffix().toLower() == "off")
@@ -68,6 +72,24 @@ public:
      }
      Scene_surface_mesh_item* item = new Scene_surface_mesh_item(surface_mesh);
      item->setName(fileinfo.completeBaseName());
+     std::size_t isolated_v = 0;
+     BOOST_FOREACH(vertex_descriptor v, vertices(*surface_mesh))
+     {
+       if(surface_mesh->is_isolated(v))
+       {
+         ++isolated_v;
+       }
+     }
+     if(isolated_v >0)
+     {
+       item->setNbIsolatedvertices(isolated_v);
+       //needs two restore, it's not a typo
+       QApplication::restoreOverrideCursor();
+       QMessageBox::warning((QWidget*)NULL,
+                      tr("Isolated vertices"),
+                      tr("%1 isolated vertices found")
+                      .arg(item->getNbIsolatedvertices()));
+     }
      return item;
      }
      else if(fileinfo.suffix().toLower() == "obj")
@@ -86,8 +108,8 @@ public:
      return 0;
 
    }
-   bool canSave(const CGAL::Three::Scene_item* ) {
-     return true;
+   bool canSave(const CGAL::Three::Scene_item* item) {
+       return qobject_cast<const Scene_surface_mesh_item*>(item) != 0;
    }
 
    bool save(const CGAL::Three::Scene_item* item, QFileInfo fileinfo) {
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
index 1df8a8f2b6f..88ee9889a1b 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
@@ -195,16 +195,36 @@ public:
     lastMatrix.setToIdentity();
     mw = _mw;
     this->scene = scene_interface;
-    actionTransformPolyhedron = new QAction("Affine Transformation", mw);
+
+
+    actionTransformPolyhedron = new QAction(
+      #ifdef CGAL_USE_SURFACE_MESH
+                tr("Affine Transformation for Surface Mesh")
+      #else
+                tr("Affine Transformation for Polyhedron")
+      #endif
+          , mw);
     if(actionTransformPolyhedron) {
       connect(actionTransformPolyhedron, SIGNAL(triggered()),this, SLOT(go()));
     }
     transform_item = NULL;
     transform_points_item = NULL;
 
-    dock_widget = new QDockWidget(mw);
+    dock_widget = new QDockWidget(
+      #ifdef CGAL_USE_SURFACE_MESH
+          tr("Affine Transformation for Surface Mesh")
+      #else
+          tr("Affine Transformation for Polyhedron")
+      #endif
+          , mw);
     ui.setupUi(dock_widget);
-
+    dock_widget->setWindowTitle(tr(
+                              #ifdef CGAL_USE_SURFACE_MESH
+                                  "Affine Transformation for Surface Mesh"
+                              #else
+                                  "Affine Transformation for Polyhedron"
+                              #endif
+                                  ));
     addDockWidget(dock_widget);
     dock_widget->hide();
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PCA/Clipping_box_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PCA/Clipping_box_plugin.cpp
index 618fe29f454..d1b7e6f5e7e 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PCA/Clipping_box_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PCA/Clipping_box_plugin.cpp
@@ -88,6 +88,12 @@ dock_widget->show();
     item = new Scene_edit_box_item(scene);
   connect(item, SIGNAL(destroyed()),
           this, SLOT(enableAction()));
+  connect(item, &Scene_edit_box_item::aboutToBeDestroyed,
+          this, [this]()
+  {
+    clip(false);
+    dock_widget->pushButton->setChecked(false);
+  });
   item->setName("Clipping box");
   item->setRenderingMode(FlatPlusEdges);
   QGLViewer* viewer = *QGLViewer::QGLViewerPool().begin();
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PCA/Create_bbox_mesh_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PCA/Create_bbox_mesh_plugin.cpp
index 4d1a7471140..3aba3fbb967 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PCA/Create_bbox_mesh_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PCA/Create_bbox_mesh_plugin.cpp
@@ -27,7 +27,8 @@ public:
   void init(QMainWindow* mainWindow, Scene_interface* scene_interface, Messages_interface*);
   QList<QAction*> actions() const;
   bool applicable(QAction*) const {
-    if(scene->mainSelectionIndex() != -1)
+    if(scene->mainSelectionIndex() != -1
+       && scene->item(scene->mainSelectionIndex())->isFinite())
       return true;
   return false;}
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PCA/Scene_edit_box_item.cpp b/Polyhedron/demo/Polyhedron/Plugins/PCA/Scene_edit_box_item.cpp
index 00c09a184c8..7b743eb31b2 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PCA/Scene_edit_box_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PCA/Scene_edit_box_item.cpp
@@ -995,6 +995,8 @@ void Scene_edit_box_item_priv::reset_selection()
 //intercept events for picking
 bool Scene_edit_box_item::eventFilter(QObject *obj, QEvent *event)
 {
+  if(!visible())
+    return false;
   QGLViewer* viewer = qobject_cast<QGLViewer*>(obj);
   if(!viewer)
     return false;
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PMP/Fairing_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PMP/Fairing_plugin.cpp
index 5e8194089e3..1f4b212c807 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PMP/Fairing_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PMP/Fairing_plugin.cpp
@@ -57,16 +57,35 @@ public:
     mw = mainWindow;
     scene = scene_interface;
     messages = m;
-    actionFairing = new QAction(tr("Refinement and Fairing"), mw);
+    actionFairing = new QAction(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "Refinement and Fairing for Surface Mesh"
+                              #else
+                                  "Refinement and Fairing for Polyhedron"
+                              #endif
+                                  ), mw);
     actionFairing->setProperty("subMenuName", "Polygon Mesh Processing");
 
     connect(actionFairing, SIGNAL(triggered()), this, SLOT(fairing_action()));
 
-    dock_widget = new QDockWidget("Refinement and Fairing", mw);
+    dock_widget = new QDockWidget(
+      #ifdef USE_SURFACE_MESH
+          "Refinement and Fairing for Surface Mesh"
+      #else
+          "Refinement and Fairing for Polyhedron"
+      #endif
+                                  , mw);
     dock_widget->setVisible(false);
 
     ui_widget.setupUi(dock_widget);
     addDockWidget(dock_widget);
+    dock_widget->setWindowTitle(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "Fairing for Surface Mesh"
+                              #else
+                                  "Fairing for Polyhedron"
+                              #endif
+                                  ));
 
     connect(ui_widget.Fair_button,  SIGNAL(clicked()), this, SLOT(on_Fair_button_clicked()));  
     connect(ui_widget.Refine_button,  SIGNAL(clicked()), this, SLOT(on_Refine_button_clicked()));
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PMP/Hole_filling_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PMP/Hole_filling_plugin.cpp
index 3af8ea7ce2f..e7a5e8dff1a 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PMP/Hole_filling_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PMP/Hole_filling_plugin.cpp
@@ -435,11 +435,23 @@ void Polyhedron_demo_hole_filling_plugin::init(QMainWindow* mainWindow,
   scene = scene_interface;
   messages = m;
 
-  actionHoleFilling = new QAction(tr("Hole Filling"), mw);
+  actionHoleFilling = new QAction(tr(
+                                  #ifdef USE_SURFACE_MESH
+                                      "Hole Filling for Surface Mesh"
+                                  #else
+                                      "Hole Filling for Polyhedron"
+                                  #endif
+                                    ), mw);
   actionHoleFilling->setProperty("subMenuName", "Polygon Mesh Processing");
   connect(actionHoleFilling, SIGNAL(triggered()), this, SLOT(hole_filling_action()));
 
-  dock_widget = new QDockWidget("Hole Filling", mw);
+  dock_widget = new QDockWidget(
+      #ifdef USE_SURFACE_MESH
+          "Hole Filling for Surface Mesh"
+      #else
+          "Hole Filling for Polyhedron"
+      #endif
+        , mw);
   dock_widget->setVisible(false);
   dock_widget->installEventFilter(this);
 
@@ -448,6 +460,13 @@ void Polyhedron_demo_hole_filling_plugin::init(QMainWindow* mainWindow,
   ui_widget.Reject_button->setVisible(false);
 
   addDockWidget(dock_widget);
+  dock_widget->setWindowTitle(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "Hole Filling for Surface Mesh"
+                              #else
+                                  "Hole Filling for Polyhedron"
+                              #endif
+                                ));
   
   connect(ui_widget.Fill_from_selection_button,  SIGNAL(clicked()), this, SLOT(on_Fill_from_selection_button()));
   connect(ui_widget.Visualize_holes_button,  SIGNAL(clicked()), this, SLOT(on_Visualize_holes_button()));
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 f1b49b47b2f..e0b0f6e36cb 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
@@ -118,7 +118,13 @@ public:
     dockWidget = NULL;
     ui = NULL;
 
-    actionMCFSkeleton = new QAction(tr("Mean Curvature Skeleton (Advanced)"), mainWindow);
+    actionMCFSkeleton = new QAction(tr(
+                                  #ifdef USE_SURFACE_MESH
+                                      "Mean Curvature Skeleton (Advanced) for Surface Mesh"
+                                  #else
+                                      "Mean Curvature Skeleton (Advanced) for Polyhedron"
+                                  #endif
+                                      ), mainWindow);
     actionMCFSkeleton->setProperty("subMenuName", "Triangulated Surface Mesh Skeletonization");
     actionMCFSkeleton->setObjectName("actionMCFSkeleton");
 
@@ -126,14 +132,26 @@ public:
     actionConvert_to_medial_skeleton->setProperty("subMenuName", "Triangulated Surface Mesh Skeletonization");
     actionConvert_to_medial_skeleton->setObjectName("actionConvert_to_medial_skeleton");
 
-    dockWidget = new QDockWidget(mw);
+    dockWidget = new QDockWidget(tr(
+                               #ifdef USE_SURFACE_MESH
+                                   "Mean Curvature Skeleton for Surface Mesh"
+                               #else
+                                   "Mean Curvature Skeleton for Polyhedron"
+                               #endif
+                                   ),mw);
     dockWidget->setVisible(false);
     ui = new Ui::Mean_curvature_flow_skeleton_plugin();
     ui->setupUi(dockWidget);
     dockWidget->setFeatures(QDockWidget::DockWidgetMovable
                           | QDockWidget::DockWidgetFloatable
                           | QDockWidget::DockWidgetClosable);
-    dockWidget->setWindowTitle("Mean Curvature Flow Skeleton");
+    dockWidget->setWindowTitle(tr(
+                             #ifdef USE_SURFACE_MESH
+                               "Mean Curvature Skeleton for Surface Mesh"
+                           #else
+                               "Mean Curvature Skeleton for Polyhedron"
+                           #endif
+                                 ));
     addDockWidget(dockWidget);
 
     connect(ui->pushButton_contract, SIGNAL(clicked()),
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_plugin.cpp
index 335777f6303..f299fcbeb1b 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_plugin.cpp
@@ -3,6 +3,8 @@
 #include <CGAL/Polygon_2.h>
 #include <QtCore/qglobal.h>
 #include <QGLViewer/manipulatedCameraFrame.h>
+#include <CGAL/Search_traits_3.h>
+#include <CGAL/Orthogonal_k_neighbor_search.h>
 #include "opengl_tools.h"
 
 #include "Messages_interface.h"
@@ -22,6 +24,7 @@
 #include <QEvent>
 #include <QKeyEvent>
 #include <QMouseEvent>
+#include <QMessageBox>
 
 #include <map>
 #include <fstream>
@@ -225,10 +228,18 @@ public:
 
     connect(ui_widget.box, SIGNAL(toggled(bool)), 
             this, SLOT(on_box_toggled(bool)));
+    connect(ui_widget.helpButton, &QAbstractButton::clicked,
+    [this](){
+      QMessageBox::information(dock_widget, QString("Help"),
+                               QString("SHIFT + Left Click : selection\n"
+                                       "CONTROL + Left Click : print coordinates of point under cursor."));
+    }
+  );
 
     visualizer = NULL;
     edit_box = NULL;
     shift_pressing = false;
+    ctrl_pressing = false;
     
     QGLViewer* viewer = *QGLViewer::QGLViewerPool().begin();
     viewer->installEventFilter(this);
@@ -260,6 +271,7 @@ protected:
       Qt::KeyboardModifiers modifiers = keyEvent->modifiers();
 
       shift_pressing = modifiers.testFlag(Qt::ShiftModifier);
+      ctrl_pressing = modifiers.testFlag(Qt::ControlModifier);
 #if QGLVIEWER_VERSION >= 0x020700
       background = static_cast<CGAL::Three::Viewer_interface*>(*QGLViewer::QGLViewerPool().begin())->grabFramebuffer();
 #else
@@ -310,7 +322,32 @@ protected:
         visualizer->sample_mouse_path(background);
 	return true;
       }
+    //Position request
+    else if(ctrl_pressing && event->type() == QEvent::MouseButtonPress)
+    {
+      QMouseEvent* m_e = static_cast<QMouseEvent*>(event);
+      Scene_points_with_normal_item* item =
+          qobject_cast<Scene_points_with_normal_item*>(scene->item(scene->mainSelectionIndex()));
+      if(!item)
+        return false;
+      QGLViewer* viewer = *QGLViewer::QGLViewerPool().begin();
+      bool found = false;
+      QPoint pixel(m_e->pos().x(),
+             viewer->camera()->screenHeight()-1-m_e->pos().y());
+      qglviewer::Vec point = viewer->camera()->pointUnderPixel(m_e->pos(),
+                                                               found);
+      if(!found)
+        return false;
+      typedef Kernel::Point_3 Point;
+      typedef CGAL::Search_traits_3<Kernel> TreeTraits;
+      typedef CGAL::Orthogonal_k_neighbor_search<TreeTraits> Neighbor_search;
+      typedef Neighbor_search::Tree Tree;
+      Tree tree(item->point_set()->points().begin(), item->point_set()->points().end());
 
+      Neighbor_search search(tree, Point(point.x, point.y, point.z), 1);
+      Point res = search.begin()->first;
+      messages->information(QString("Selected point : (%1, %2, %3)").arg(res.x()).arg(res.y()).arg(res.z()));
+    }
     return false;
   }
 
@@ -563,6 +600,7 @@ public Q_SLOTS:
 
   }
 
+
   void reset_editbox()
   {
     edit_box = NULL;
@@ -578,6 +616,7 @@ private:
   Ui::PointSetSelection ui_widget;
   Scene_point_set_selection_visualizer* visualizer;
   bool shift_pressing;
+  bool ctrl_pressing;
   Scene_edit_box_item* edit_box;
 
 }; // end Polyhedron_demo_point_set_selection_plugin
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_widget.ui b/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_widget.ui
index 04680455563..a928273065f 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_widget.ui
+++ b/Polyhedron/demo/Polyhedron/Plugins/Point_set/Point_set_selection_widget.ui
@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>389</width>
-    <height>101</height>
+    <width>514</width>
+    <height>281</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -254,6 +254,26 @@
         </property>
        </widget>
       </item>
+      <item>
+       <widget class="QPushButton" name="helpButton">
+        <property name="text">
+         <string/>
+        </property>
+        <property name="icon">
+         <iconset resource="../../Polyhedron_3.qrc">
+          <normaloff>:/cgal/icons/resources/help_button.png</normaloff>:/cgal/icons/resources/help_button.png</iconset>
+        </property>
+        <property name="iconSize">
+         <size>
+          <width>16</width>
+          <height>16</height>
+         </size>
+        </property>
+        <property name="flat">
+         <bool>false</bool>
+        </property>
+       </widget>
+      </item>
       <item>
        <spacer name="horizontalSpacer">
         <property name="orientation">
@@ -287,6 +307,9 @@
  </widget>
  <resources>
   <include location="../../Polyhedron_3.qrc"/>
+  <include location="../../Polyhedron_3.qrc"/>
+  <include location="../../Polyhedron_3.qrc"/>
+  <include location="../../Polyhedron_3.qrc"/>
  </resources>
  <connections/>
 </ui>
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
index ca2f0dfdbd0..afce55e99f6 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Parameterization_plugin.cpp
@@ -385,9 +385,27 @@ public:
     autoConnectActions();
     Q_FOREACH(QAction *action, _actions)
       action->setProperty("subMenuName",
-                          "Triangulated Surface Mesh Parameterization");
-    dock_widget = new QDockWidget("UVMapping", mw);
+                    #ifdef USE_SURFACE_MESH
+                          "Triangulated Surface Mesh Parameterization"
+                    #else
+                          "Triangulated Surface Mesh Parameterization for Polyhedron"
+                    #endif
+                          );
+    dock_widget = new QDockWidget(
+      #ifdef USE_SURFACE_MESH
+          "UVMapping for Surface Mesh"
+      #else
+          "UVMapping for Polyhedron"
+      #endif
+          , mw);
     ui_widget.setupUi(dock_widget);
+    dock_widget->setWindowTitle(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "UVMapping for Surface Mesh"
+                              #else
+                                  "UVMapping for Polyhedron"
+                              #endif
+                                  ));
     graphics_scene = new QGraphicsScene(dock_widget);
     ui_widget.graphicsView->setScene(graphics_scene);
     ui_widget.graphicsView->setRenderHints(QPainter::Antialiasing);
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Shortest_path_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Shortest_path_plugin.cpp
index 003a08c4c0b..8ecc9053a6b 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Shortest_path_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Surface_mesh/Shortest_path_plugin.cpp
@@ -89,17 +89,36 @@ public:
     this->mw = mainWindow;
     this->m_messages = messages;
 
-    dock_widget = new QDockWidget("Shortest path", mw);
+    dock_widget = new QDockWidget(
+      #ifdef USE_SURFACE_MESH
+          "Shortest Path for Surface Mesh"
+      #else
+          "Shortest Path for Polyhedron"
+      #endif
+          , mw);
 
     dock_widget->setVisible(false);
 
     ui_widget.setupUi(dock_widget);
+    dock_widget->setWindowTitle(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "Shortest Path for Surface Mesh"
+                              #else
+                                  "Shortest Path for Polyhedron"
+                              #endif
+                                  ));
     addDockWidget(dock_widget);
 
     connect(ui_widget.Selection_type_combo_box, SIGNAL(currentIndexChanged(int)),  this, SLOT(on_Selection_type_combo_box_changed(int)));
     connect(ui_widget.Primitives_type_combo_box, SIGNAL(currentIndexChanged(int)), this, SLOT(on_Primitives_type_combo_box_changed(int)));
 
-    actionMakeShortestPaths = new QAction("Make Shortest Path", this->mw);
+    actionMakeShortestPaths = new QAction(
+      #ifdef USE_SURFACE_MESH
+          "Make Shortest Path for Surface Mesh"
+      #else
+          "Make Shortest Path for Polyhedron"
+      #endif
+          , this->mw);
     actionMakeShortestPaths->setProperty("subMenuName", "Triangulated Surface Mesh Shortest Paths");
     actionMakeShortestPaths->setObjectName("actionMakeShortestPaths");
 
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 8493ea9ed47..854b6b56f10 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
@@ -126,7 +126,13 @@ void Polyhedron_demo_edit_polyhedron_plugin::init(QMainWindow* mainWindow, CGAL:
 {
   mw = mainWindow;
   scene = scene_interface;
-  actionDeformation = new QAction("Surface Mesh Deformation", mw);
+  actionDeformation = new QAction(
+      #ifdef USE_SURFACE_MESH
+          "Surface Mesh Deformation"
+      #else
+          " Polyhedron Deformation"
+      #endif
+        , mw);
   actionDeformation->setProperty("subMenuName", "Triangulated Surface Mesh Deformation");
   actionDeformation->setObjectName("actionDeformation");
   actionDeformation->setShortcutContext(Qt::ApplicationShortcut);
@@ -140,10 +146,24 @@ void Polyhedron_demo_edit_polyhedron_plugin::init(QMainWindow* mainWindow, CGAL:
 
   ////////////////// Construct widget /////////////////////////////
   // First time, construct docking window
-  dock_widget = new QDockWidget("Mesh Deformation", mw);
+  dock_widget = new QDockWidget(
+      #ifdef USE_SURFACE_MESH
+          "Surface Mesh Deformation"
+      #else
+          " Polyhedron Deformation"
+      #endif
+        , mw);
   dock_widget->setVisible(false); // do not show at the beginning
 
   ui_widget.setupUi(dock_widget); 
+  dock_widget->setWindowTitle(tr(
+                              #ifdef USE_SURFACE_MESH
+                                  "Surface Mesh Deformation"
+                              #else
+                                  " Polyhedron Deformation"
+                              #endif
+                                ));
+
   mw->addDockWidget(Qt::LeftDockWidgetArea, dock_widget);
 
   connect(ui_widget.AddCtrlVertPushButton, SIGNAL(clicked()), this, SLOT(on_AddCtrlVertPushButton_clicked()));
diff --git a/Polyhedron/demo/Polyhedron/Polyhedron_3.qrc b/Polyhedron/demo/Polyhedron/Polyhedron_3.qrc
index ca73b090935..1f8e93f2977 100644
--- a/Polyhedron/demo/Polyhedron/Polyhedron_3.qrc
+++ b/Polyhedron/demo/Polyhedron/Polyhedron_3.qrc
@@ -29,6 +29,7 @@
         <file>resources/pss_union.png</file>
         <file>resources/pss_inter.png</file>
         <file>resources/pss_diff.png</file>
+        <file>resources/help_button.png</file>
     </qresource>
     <qresource prefix="/cgal/Polyhedron_3">
         <file alias="about.html">resources/about.html</file>
diff --git a/Polyhedron/demo/Polyhedron/Scene.cpp b/Polyhedron/demo/Polyhedron/Scene.cpp
index 279b8f4f981..1b1b7970b7b 100644
--- a/Polyhedron/demo/Polyhedron/Scene.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene.cpp
@@ -217,6 +217,15 @@ Scene::erase(QList<int> indices)
        && item->parentGroup()->isChildLocked(item))
       if(!indices.contains(item_id(item->parentGroup())))
         continue;
+    Scene_group_item* group = qobject_cast<Scene_group_item*>(item);
+    if(group)
+    {
+      Q_FOREACH(Scene_item* child, group->getChildren())
+      {
+        if(!to_be_removed.contains(child))
+          to_be_removed.push_back(child);
+      }
+    }
     if(!to_be_removed.contains(item))
       to_be_removed.push_back(item);
   }
@@ -781,6 +790,10 @@ Scene::setData(const QModelIndex &index,
         return true;
         break;
     case ColorColumn:
+      if(!selectionIndices().empty())
+        Q_FOREACH(Item_id item_index, selectionIndices())
+          this->item(item_index)->setColor(value.value<QColor>());
+      else
         item->setColor(value.value<QColor>());
     Q_EMIT dataChanged(index, index);
         return true;
diff --git a/Polyhedron/demo/Polyhedron/Scene.h b/Polyhedron/demo/Polyhedron/Scene.h
index ea399e3ce66..e889bcf4403 100644
--- a/Polyhedron/demo/Polyhedron/Scene.h
+++ b/Polyhedron/demo/Polyhedron/Scene.h
@@ -191,7 +191,7 @@ public Q_SLOTS:
        if(group)
        {
          QList<int> list;
-         Q_FOREACH(CGAL::Three::Scene_item* child, group->getChildren())
+         Q_FOREACH(CGAL::Three::Scene_item* child, group->getChildrenForSelection())
            list<<m_entries.indexOf(child);
          l << setSelectedItemsList(list);
        }
diff --git a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
index e3b7b94a5ea..325c614bd50 100644
--- a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
@@ -47,6 +47,7 @@ public :
   {
     setParent(parent);
   }
+  bool isFinite() const { return false; }
   void init_vectors(
       std::vector<float> *p_vertices,
       std::vector<float> *p_normals,
@@ -298,7 +299,6 @@ struct Scene_c3t3_item_priv {
     tree.clear();
     if(frame)
     {
-      static_cast<CGAL::Three::Viewer_interface*>(QGLViewer::QGLViewerPool().first())->setManipulatedFrame(0);
       delete frame;
       frame = NULL;
       delete tet_Slider;
@@ -317,7 +317,7 @@ struct Scene_c3t3_item_priv {
     intersection = NULL;
     spheres_are_shown = false;
     cnc_are_shown = false;
-    show_tetrahedra = false;
+    show_tetrahedra = true;
     is_aabb_tree_built = false;
     are_intersection_buffers_filled = false;
     is_grid_shown = true;
@@ -915,6 +915,7 @@ void Scene_c3t3_item::draw(CGAL::Three::Viewer_interface* viewer) const {
   vaos[Scene_c3t3_item_priv::Facets]->release();
 
   if(d->show_tetrahedra){
+    ncthis->show_intersection(true);
     if(!d->frame->isManipulated())
       d->intersection->setFast(false);
     else
@@ -925,6 +926,7 @@ void Scene_c3t3_item::draw(CGAL::Three::Viewer_interface* viewer) const {
       ncthis->d->computeIntersections();
       d->intersection->initialize_buffers(viewer);
       d->are_intersection_buffers_filled = true;
+      ncthis->show_intersection(true);
     }
   }
 
@@ -1829,7 +1831,7 @@ bool Scene_c3t3_item::keyPressEvent(QKeyEvent *event)
    d->tet_Slider->setValue(d->tet_Slider->value() -5);
    itemChanged();
  }
- return true;
+ return false;
 }
 
 QString Scene_c3t3_item::computeStats(int type)
diff --git a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.h b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.h
index 7b7cc8f1710..dde7f7a76bc 100644
--- a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.h
@@ -118,6 +118,8 @@ public:
   void draw(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE;
   void drawEdges(CGAL::Three::Viewer_interface* viewer) const Q_DECL_OVERRIDE;
   void drawPoints(CGAL::Three::Viewer_interface * viewer) const Q_DECL_OVERRIDE;
+   //When selecting a c3t3 item, we don't want to select its children, so we can still apply Operations to it
+  QList<Scene_item*> getChildrenForSelection() const Q_DECL_OVERRIDE { return QList<Scene_item*>(); }
   public:
     QMenu* contextMenu() Q_DECL_OVERRIDE;
     void copyProperties(Scene_item *) Q_DECL_OVERRIDE;
diff --git a/Polyhedron/demo/Polyhedron/Scene_item.cpp b/Polyhedron/demo/Polyhedron/Scene_item.cpp
index a785f8537fb..1cd1a602099 100644
--- a/Polyhedron/demo/Polyhedron/Scene_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_item.cpp
@@ -123,10 +123,6 @@ QMenu* CGAL::Three::Scene_item::contextMenu()
     }
 
     defaultContextMenu = new QMenu(name());
-    // defaultContextMenu->addAction(name());
-    // defaultContextMenu->addSeparator();
-    // QMenu* modeMenu = new QMenu(QObject::tr("Rendering mode"),
-    //                             defaultContextMenu);
     for(unsigned int mode = 0; mode < NumberOfRenderingMode;
         ++mode)
     {
@@ -136,8 +132,8 @@ QMenu* CGAL::Three::Scene_item::contextMenu()
                                       .arg(mName),
                                       this,
                                       slotName(RenderingMode(mode)));
+        defaultContextMenu->actions().last()->setProperty("is_groupable", true);
     }
-    // defaultContextMenu->addAction(modeMenu->menuAction());
     return defaultContextMenu;
 }
 
diff --git a/Polyhedron/demo/Polyhedron/Scene_points_with_normal_item.cpp b/Polyhedron/demo/Polyhedron/Scene_points_with_normal_item.cpp
index 457a72d9aba..68b55bb7b56 100644
--- a/Polyhedron/demo/Polyhedron/Scene_points_with_normal_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_points_with_normal_item.cpp
@@ -168,8 +168,11 @@ Scene_points_with_normal_item::Scene_points_with_normal_item(const Scene_points_
         setRenderingMode(Points);
         is_selected = true;
     }
-
-    invalidateOpenGLBuffers();
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
+  invalidateOpenGLBuffers();
 }
 
 // Converts polyhedron to point set
@@ -182,6 +185,10 @@ Scene_points_with_normal_item::Scene_points_with_normal_item(const SMesh& input_
   d = new Scene_points_with_normal_item_priv(input_mesh, this);
   setRenderingMode(PointsPlusNormals);
   is_selected = true;
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
   invalidateOpenGLBuffers();
 }
 
@@ -193,6 +200,10 @@ Scene_points_with_normal_item::Scene_points_with_normal_item(const Polyhedron& i
   d = new Scene_points_with_normal_item_priv(input_mesh, this);
   setRenderingMode(PointsPlusNormals);
   is_selected = true;
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
   invalidateOpenGLBuffers();
 }
 
@@ -369,10 +380,6 @@ void Scene_points_with_normal_item_priv::compute_normals_and_vertices() const
     normals.resize(0);
     colors_points.resize(0);
 
-    if(item->point_set()->number_of_points() < 30 )
-      point_Slider->setValue(5);
-    else
-      point_Slider->setValue(2);
     //Shuffle container to allow quick display random points
     std::random_shuffle (m_points->begin(), m_points->first_selected());
     if (m_points->nb_selected_points() != 0)
@@ -594,7 +601,10 @@ bool Scene_points_with_normal_item::read_ply_point_set(std::istream& stream)
   bool ok = stream &&
     CGAL::read_ply_point_set (stream, *(d->m_points), &(d->m_comments)) &&
             !isEmpty();
-
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
   std::cerr << d->m_points->info();
 
   if (d->m_points->has_normal_map())
@@ -637,6 +647,10 @@ bool Scene_points_with_normal_item::read_off_point_set(std::istream& stream)
   bool ok = stream &&
     CGAL::read_off_point_set(stream, *(d->m_points)) &&
             !isEmpty();
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
   invalidateOpenGLBuffers();
   return ok;
 }
@@ -662,7 +676,10 @@ bool Scene_points_with_normal_item::read_xyz_point_set(std::istream& stream)
   bool ok = stream &&
     CGAL::read_xyz_point_set (stream, *(d->m_points)) &&
     !isEmpty();
-
+  if(d->m_points->number_of_points() < 30 )
+    d->point_Slider->setValue(5);
+  else
+    d->point_Slider->setValue(2);
   invalidateOpenGLBuffers();
   return ok;
 }
@@ -1004,7 +1021,8 @@ void Scene_points_with_normal_item::copyProperties(Scene_item *item)
   Scene_points_with_normal_item* point_item = qobject_cast<Scene_points_with_normal_item*>(item);
   if(!point_item)
     return;
-  d->point_Slider->setValue(point_item->getPointSliderValue());
+  int value = point_item->getPointSliderValue();
+  setPointSize(value);
   if(has_normals())
     d->normal_Slider->setValue(point_item->getNormalSliderValue());
 }
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
index 1dabf35592b..8b4b8fad5c6 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
@@ -121,10 +121,9 @@ struct Scene_polyhedron_item_priv{
     nb_f_lines = 0;
     is_multicolor = false;
     no_flat = false;
-    vertices_displayed = true;
-    edges_displayed = true;
-    faces_displayed = true;
-    all_primitives_displayed = false;
+    vertices_displayed = false;
+    edges_displayed = false;
+    faces_displayed = false;
     invalidate_stats();
     CGAL::set_halfedgeds_items_id(*poly);
   }
@@ -189,7 +188,6 @@ struct Scene_polyhedron_item_priv{
   mutable bool vertices_displayed;
   mutable bool edges_displayed;
   mutable bool faces_displayed;
-  mutable bool all_primitives_displayed;
   mutable QList<double> text_ids;
   mutable std::vector<TextItem*> targeted_id;
   void initialize_buffers(CGAL::Three::Viewer_interface *viewer = 0) const;
@@ -1078,7 +1076,7 @@ Scene_polyhedron_item::toolTip() const
          QObject::tr("<p>Polyhedron_3 <b>%1</b> (mode: %5, color: %6)</p>"
                        "<p>Number of vertices: %2<br />"
                        "Number of edges: %3<br />"
-                     "Number of facets: %4")
+                     "Number of faces: %4")
             .arg(this->name())
             .arg(d->poly->size_of_vertices())
             .arg(d->poly->size_of_halfedges()/2)
@@ -1142,13 +1140,6 @@ QMenu* Scene_polyhedron_item::contextMenu()
     connect(actionPrintFaces, SIGNAL(triggered(bool)),
             this, SLOT(showFaces(bool)));
 
-    QAction* actionPrintAll=
-        menu->addAction(tr("Display All Ids"));
-    actionPrintAll->setCheckable(true);
-    actionPrintAll->setObjectName("actionPrintAll");
-    connect(actionPrintAll, SIGNAL(triggered(bool)),
-            this, SLOT(showPrimitives(bool)));
-
     QAction* actionZoomToId=
         menu->addAction(tr("Zoom to Index"));
     actionZoomToId->setObjectName("actionZoomToId");
@@ -1212,8 +1203,6 @@ QMenu* Scene_polyhedron_item::contextMenu()
   if(action) action->setChecked(d->edges_displayed);
   action = menu->findChild<QAction*>("actionPrintFaces");
   if(action) action->setChecked(d->faces_displayed);
-  action = menu->findChild<QAction*>("actionPrintAll");
-  if(action) action->setChecked(d->all_primitives_displayed);
 
   return menu;
 }
@@ -1845,8 +1834,6 @@ CGAL::Three::Scene_item::Header_data Scene_polyhedron_item::header() const
 
 void Scene_polyhedron_item::printPrimitiveId(QPoint point, CGAL::Three::Viewer_interface *viewer)
 {
-  if(d->all_primitives_displayed)
-    return;
   typedef Input_facets_AABB_tree Tree;
   Tree* aabb_tree = static_cast<Input_facets_AABB_tree*>(d->get_aabb_tree());
   if(!aabb_tree)
@@ -1871,8 +1858,7 @@ void Scene_polyhedron_item_priv::fillTargetedIds(const Polyhedron::Facet_handle&
                         textVItems,
                         textEItems,
                         textFItems,
-                        &targeted_id,
-                        &all_primitives_displayed);
+                        &targeted_id);
 
 
   if(vertices_displayed
@@ -1928,8 +1914,7 @@ void Scene_polyhedron_item_priv::killIds()
             textVItems,
             textEItems,
             textFItems,
-            &targeted_id,
-            &all_primitives_displayed);
+            &targeted_id);
 }
 
 void Scene_polyhedron_item::printAllIds(CGAL::Three::Viewer_interface *viewer)
@@ -1944,7 +1929,6 @@ void Scene_polyhedron_item::printAllIds(CGAL::Three::Viewer_interface *viewer)
         s3(printFaceIds(viewer));
     if((s1 && s2 && s3))
     {
-      d->all_primitives_displayed = true;
       viewer->update();
     }
     return;
@@ -2251,6 +2235,9 @@ void Scene_polyhedron_item::zoomToId()
   QString text = QInputDialog::getText(QApplication::activeWindow(), tr("Zoom to Index"),
                                        tr("Simplex"), QLineEdit::Normal,
                                        tr("v0"), &ok);
+  if(!ok)
+    return;
+
   CGAL::Three::Viewer_interface* viewer =
       qobject_cast<CGAL::Three::Viewer_interface*>(QGLViewer::QGLViewerPool().first());
   Point p;
diff --git a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
index 8fd8db1dcc8..93bf7e18f11 100644
--- a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
@@ -88,10 +88,9 @@ struct Scene_surface_mesh_item_priv{
     item = parent;
     has_feature_edges = false;
     invalidate_stats();
-    vertices_displayed = true;
-    edges_displayed = true;
-    faces_displayed = true;
-    all_primitives_displayed = false;
+    vertices_displayed = false;
+    edges_displayed = false;
+    faces_displayed = false;
   }
 
   Scene_surface_mesh_item_priv(SMesh* sm, Scene_surface_mesh_item *parent):
@@ -100,10 +99,9 @@ struct Scene_surface_mesh_item_priv{
     item = parent;
     has_feature_edges = false;
     invalidate_stats();
-    vertices_displayed = true;
-    edges_displayed = true;
-    faces_displayed = true;
-    all_primitives_displayed = false;
+    vertices_displayed = false;
+    edges_displayed = false;
+    faces_displayed = false;
   }
 
   ~Scene_surface_mesh_item_priv()
@@ -165,7 +163,6 @@ struct Scene_surface_mesh_item_priv{
   mutable bool vertices_displayed;
   mutable bool edges_displayed;
   mutable bool faces_displayed;
-  mutable bool all_primitives_displayed;
   mutable QList<double> text_ids;
   mutable std::vector<TextItem*> targeted_id;
 
@@ -774,16 +771,18 @@ Scene_surface_mesh_item::isEmpty() const
 
 QString Scene_surface_mesh_item::toolTip() const
 {
-  return QObject::tr("<p>Surface_mesh <b>%1</b> (mode: %5, color: %6)</p>"
-                     "<p>Number of vertices: %2<br />"
-                     "Number of edges: %3<br />"
-                     "Number of faces: %4</p>")
-    .arg(this->name())
-    .arg(num_vertices(*d->smesh_))
-    .arg(num_edges(*d->smesh_))
-    .arg(num_faces(*d->smesh_))
-    .arg(this->renderingModeName())
-    .arg(this->color().name());
+  QString str = QObject::tr("<p>Surface_mesh <b>%1</b> (mode: %5, color: %6)</p>"
+                            "<p>Number of vertices: %2<br />"
+                            "Number of edges: %3<br />"
+                            "Number of faces: %4</p>")
+      .arg(this->name())
+      .arg(num_vertices(*d->smesh_))
+      .arg(num_edges(*d->smesh_))
+      .arg(num_faces(*d->smesh_))
+      .arg(this->renderingModeName())
+      .arg(this->color().name());
+  str += QString("<br />Number of isolated vertices: %1<br />").arg(getNbIsolatedvertices());
+  return str;
 }
 
 void Scene_surface_mesh_item_priv::checkFloat()const
@@ -1706,12 +1705,6 @@ QMenu* Scene_surface_mesh_item::contextMenu()
     connect(actionPrintFaces, SIGNAL(triggered(bool)),
             this, SLOT(showFaces(bool)));
 
-    QAction* actionPrintAll=
-        menu->addAction(tr("Display All Ids"));
-    actionPrintAll->setCheckable(true);
-    actionPrintAll->setObjectName("actionPrintAll");
-    connect(actionPrintAll, SIGNAL(triggered(bool)),
-            this, SLOT(showPrimitives(bool)));
 
     QAction* actionZoomToId=
         menu->addAction(tr("Zoom to Index"));
@@ -1727,14 +1720,10 @@ QMenu* Scene_surface_mesh_item::contextMenu()
   if(action) action->setChecked(d->edges_displayed);
   action = menu->findChild<QAction*>("actionPrintFaces");
   if(action) action->setChecked(d->faces_displayed);
-  action = menu->findChild<QAction*>("actionPrintAll");
-  if(action) action->setChecked(d->all_primitives_displayed);
   return menu;
 }
 void Scene_surface_mesh_item::printPrimitiveId(QPoint point, CGAL::Three::Viewer_interface *viewer)
 {
-  if(d->all_primitives_displayed)
-    return;
   typedef Input_facets_AABB_tree Tree;
   Tree* aabb_tree = static_cast<Input_facets_AABB_tree*>(d->get_aabb_tree());
   if(!aabb_tree)
@@ -1759,8 +1748,7 @@ void Scene_surface_mesh_item_priv::fillTargetedIds(const face_descriptor &select
                         textVItems,
                         textEItems,
                         textFItems,
-                        &targeted_id,
-                        &all_primitives_displayed);
+                        &targeted_id);
 
 
   if(vertices_displayed
@@ -1816,8 +1804,7 @@ void Scene_surface_mesh_item_priv::killIds()
             textVItems,
             textEItems,
             textFItems,
-            &targeted_id,
-            &all_primitives_displayed);
+            &targeted_id);
 }
 
 void Scene_surface_mesh_item::printAllIds(CGAL::Three::Viewer_interface *viewer)
@@ -1832,7 +1819,6 @@ void Scene_surface_mesh_item::printAllIds(CGAL::Three::Viewer_interface *viewer)
         s3(printFaceIds(viewer));
     if((s1 && s2 && s3))
     {
-      d->all_primitives_displayed = true;
       viewer->update();
     }
     return;
@@ -1887,7 +1873,7 @@ void Scene_surface_mesh_item::showEdges(bool b)
     if(d->textEItems->isEmpty())
     {
       d->edges_displayed = b;
-      printFaceIds(viewer);
+      printEdgeIds(viewer);
     }
     else
       renderer->addTextList(d->textEItems);
@@ -1932,6 +1918,9 @@ void Scene_surface_mesh_item::zoomToId()
   QString text = QInputDialog::getText(QApplication::activeWindow(), tr("Zoom to Index"),
                                        tr("Simplex"), QLineEdit::Normal,
                                        tr("v0"), &ok);
+  if(!ok)
+    return;
+
   CGAL::Three::Viewer_interface* viewer =
       qobject_cast<CGAL::Three::Viewer_interface*>(QGLViewer::QGLViewerPool().first());
   Point_3 p;
diff --git a/Polyhedron/demo/Polyhedron/Viewer.cpp b/Polyhedron/demo/Polyhedron/Viewer.cpp
index a8fa406f39f..3193e9978cd 100644
--- a/Polyhedron/demo/Polyhedron/Viewer.cpp
+++ b/Polyhedron/demo/Polyhedron/Viewer.cpp
@@ -53,9 +53,9 @@ public:
   };
 
   //! The buffers used to draw the axis system
-  QOpenGLBuffer buffers[4];
+  QOpenGLBuffer buffers[8];
   //! The VAO used to draw the axis system
-  QOpenGLVertexArrayObject vao[2];
+  QOpenGLVertexArrayObject vao[4];
   //! The rendering program used to draw the axis system
   QOpenGLShaderProgram rendering_program;
   //! The rendering program used to draw the distance
@@ -69,6 +69,9 @@ public:
   std::vector<float> c_Axis;
   //! Decides if the axis system must be drawn or not
   bool axis_are_displayed;
+  bool grid_is_displayed;
+  std::size_t grid_size;
+  std::size_t v_gaxis_size;
   //! Decides if the text is displayed in the drawVisualHints function.
   bool has_text;
   //! Decides if the distance between APoint and BPoint must be drawn;
@@ -96,6 +99,7 @@ public:
    * \param data the struct of std::vector that will contain the results.
    */
   void makeArrow(double R, int prec, qglviewer::Vec from, qglviewer::Vec to, qglviewer::Vec color, AxisData &data);
+  void drawGrid(qreal size, int nbSubdivisions=10);
   //!Clears the distance display
   void clearDistancedisplay();
   void draw_aux(bool with_names, Viewer*);
@@ -138,6 +142,8 @@ Viewer::Viewer(QWidget* parent, bool antialiasing)
                       tr("Toggle the primitive IDs visibility of the selected Item."));
   setKeyDescription(Qt::Key_D,
                       tr("Disable the distance between two points  visibility."));
+  setKeyDescription(Qt::Key_F5,
+                    tr("Reload selected items if possible."));
 
 #if QGLVIEWER_VERSION >= 0x020501
   //modify mouse bindings that have been updated
@@ -168,6 +174,8 @@ Viewer::Viewer(QWidget* parent, bool antialiasing)
 #endif // QGLVIEWER_VERSION >= 2.5.0
   prev_radius = sceneRadius();
   d->axis_are_displayed = true;
+  d->grid_is_displayed = false;
+  d->grid_size = 0;
   d->has_text = false;
   d->i_is_pressed = false;
   d->z_is_pressed = false;
@@ -398,6 +406,12 @@ void Viewer::initializeGL()
      {
          d->vao[1].create();
          d->buffers[3].create();
+         d->vao[2].create();
+         d->vao[3].create();
+         d->buffers[4].create();
+         d->buffers[5].create();
+         d->buffers[6].create();
+         d->buffers[7].create();
          //Vertex source code
          const char vertex_source_dist[] =
          {
@@ -557,6 +571,10 @@ void Viewer::keyPressEvent(QKeyEvent* e)
           d->axis_are_displayed = !d->axis_are_displayed;
           update();
         }
+    else if(e->key() == Qt::Key_G) {
+          d->grid_is_displayed = !d->grid_is_displayed;
+          update();
+        }
     else if(e->key() == Qt::Key_I) {
           d->i_is_pressed = true;
         }
@@ -1141,6 +1159,71 @@ void Viewer::drawVisualHints()
         glLineWidth(1.0f);
 
     }
+    if(d->grid_is_displayed)
+    {
+      //draws the distance
+      QMatrix4x4 mvpMatrix;
+      double mat[16];
+      //camera()->frame()->rotation().getMatrix(mat);
+      camera()->getModelViewProjectionMatrix(mat);
+      //nullifies the translation
+      for(int i=0; i < 16; i++)
+      {
+          mvpMatrix.data()[i] = (float)mat[i];
+      }
+      d->rendering_program_dist.bind();
+      d->rendering_program_dist.setUniformValue("mvp_matrix", mvpMatrix);
+      d->vao[2].bind();
+      glDrawArrays(GL_LINES, 0, static_cast<GLsizei>(d->grid_size));
+      d->vao[2].release();
+      d->rendering_program_dist.release();
+
+      d->rendering_program.bind();
+        QMatrix4x4 mvMatrix;
+        for(int i=0; i < 16; i++)
+        {
+            mvMatrix.data()[i] = camera()->orientation().inverse().matrix()[i];
+        }
+        QVector4D	position(0.0f,0.0f,1.0f,1.0f );
+        // define material
+        QVector4D	ambient;
+        QVector4D	diffuse;
+        QVector4D	specular;
+        GLfloat      shininess ;
+        // Ambient
+        ambient[0] = 0.29225f;
+        ambient[1] = 0.29225f;
+        ambient[2] = 0.29225f;
+        ambient[3] = 1.0f;
+        // Diffuse
+        diffuse[0] = 0.50754f;
+        diffuse[1] = 0.50754f;
+        diffuse[2] = 0.50754f;
+        diffuse[3] = 1.0f;
+        // Specular
+        specular[0] = 0.0f;
+        specular[1] = 0.0f;
+        specular[2] = 0.0f;
+        specular[3] = 0.0f;
+        // Shininess
+        shininess = 51.2f;
+
+        d->rendering_program.setUniformValue("light_pos", position);
+        d->rendering_program.setUniformValue("mvp_matrix", mvpMatrix);
+        d->rendering_program.setUniformValue("mv_matrix", mvMatrix);
+        d->rendering_program.setUniformValue("light_diff", diffuse);
+        d->rendering_program.setUniformValue("light_spec", specular);
+        d->rendering_program.setUniformValue("light_amb", ambient);
+        d->rendering_program.setUniformValue("spec_power", shininess);
+
+        d->vao[3].bind();
+        // Axis viewport size, in pixels
+        glDrawArrays(GL_TRIANGLES, 0, static_cast<GLsizei>(d->v_gaxis_size / 3));
+        // The viewport and the scissor are restored.
+        d->vao[3].release();
+        d->rendering_program.release();
+    }
+
     if (!d->painter->isActive())
       d->painter->begin(this);
     //So that the text is drawn in front of everything
@@ -1325,9 +1408,6 @@ void Viewer::postDraw()
   // Pivot point, line when camera rolls, zoom region
   drawVisualHints();
 
-  if (gridIsDrawn()) { glLineWidth(1.0); drawGrid(camera()->sceneRadius()); }
-  if (axisIsDrawn()) { glLineWidth(2.0); drawAxis(camera()->sceneRadius()); }
-
   // FPS computation
   const unsigned int maxCounter = 20;
   if (++d->fpsCounter == maxCounter)
@@ -1663,6 +1743,7 @@ qglviewer::Vec Viewer::offset()const { return d->offset; }
 void Viewer::setSceneBoundingBox(const qglviewer::Vec &min, const qglviewer::Vec &max)
 {
   QGLViewer::setSceneBoundingBox(min+d->offset, max+d->offset);
+  d->drawGrid(camera()->sceneRadius());
 }
 
 void Viewer::updateIds(CGAL::Three::Scene_item * item)
@@ -1700,6 +1781,78 @@ void Viewer::enableClippingBox(QVector4D box[6])
 
 
 bool Viewer::isOpenGL_4_3() const { return d->is_ogl_4_3; }
+void Viewer_impl::drawGrid(qreal size, int nbSubdivisions)
+{
+  std::vector<float> v_Grid;
+  std::vector<float> v_gAxis;
+  std::vector<float> n_gAxis;
+  std::vector<float> c_gAxis;
+  for (int i=0; i<=nbSubdivisions; ++i)
+  {
+          const float pos = size*(2.0*i/nbSubdivisions-1.0);
+          v_Grid.push_back(pos);
+          v_Grid.push_back(-size);
+          v_Grid.push_back(0.0);
 
+          v_Grid.push_back(pos);
+          v_Grid.push_back(+size);
+          v_Grid.push_back(0.0);
+
+          v_Grid.push_back(-size);
+          v_Grid.push_back(pos);
+          v_Grid.push_back(0.0);
+
+          v_Grid.push_back( size);
+          v_Grid.push_back( pos);
+          v_Grid.push_back( 0.0);
+  }
+  rendering_program_dist.bind();
+  vao[2].bind();
+  buffers[4].bind();
+  buffers[4].allocate(v_Grid.data(),static_cast<int>(v_Grid.size()*sizeof(float)));
+  rendering_program_dist.enableAttributeArray("vertex");
+  rendering_program_dist.setAttributeBuffer("vertex",GL_FLOAT,0,3);
+  buffers[4].release();
+  vao[2].release();
+  rendering_program_dist.release();
+  grid_size = v_Grid.size();
+
+  Viewer_impl::AxisData data;
+  v_gAxis.resize(0);
+  n_gAxis.resize(0);
+  c_gAxis.resize(0);
+  data.vertices = &v_gAxis;
+  data.normals =  &n_gAxis;
+  data.colors =   &c_gAxis;
+  makeArrow(0.02*size,10, qglviewer::Vec(0,0,0),qglviewer::Vec(size,0,0),qglviewer::Vec(1,0,0), data);
+  makeArrow(0.02*size,10, qglviewer::Vec(0,0,0),qglviewer::Vec(0,size,0),qglviewer::Vec(0,1,0), data);
+  makeArrow(0.02*size,10, qglviewer::Vec(0,0,0),qglviewer::Vec(0,0,size),qglviewer::Vec(0,0,1), data);
+
+  rendering_program.bind();
+  vao[3].bind();
+  buffers[5].bind();
+  buffers[5].allocate(v_gAxis.data(), static_cast<int>(v_gAxis.size()) * sizeof(float));
+  rendering_program.enableAttributeArray("vertex");
+  rendering_program.setAttributeBuffer("vertex",GL_FLOAT,0,3);
+  buffers[5].release();
+
+  buffers[6].bind();
+  buffers[6].allocate(n_gAxis.data(), static_cast<int>(n_gAxis.size() * sizeof(float)));
+  rendering_program.enableAttributeArray("normal");
+  rendering_program.setAttributeBuffer("normal",GL_FLOAT,0,3);
+  buffers[6].release();
+
+  buffers[7].bind();
+  buffers[7].allocate(c_gAxis.data(), static_cast<int>(c_gAxis.size() * sizeof(float)));
+  rendering_program.enableAttributeArray("colors");
+  rendering_program.setAttributeBuffer("colors",GL_FLOAT,0,3);
+  buffers[7].release();
+  vao[3].release();
+
+  rendering_program.release();
+
+  v_gaxis_size = v_gAxis.size();
+
+}
 QOpenGLFunctions_4_3_Compatibility* Viewer::openGL_4_3_functions() { return d->_recentFunctions; }
  #include "Viewer.moc"
diff --git a/Polyhedron/demo/Polyhedron/include/id_printing.h b/Polyhedron/demo/Polyhedron/include/id_printing.h
index cc31d037fbe..2e97d36d2f6 100644
--- a/Polyhedron/demo/Polyhedron/include/id_printing.h
+++ b/Polyhedron/demo/Polyhedron/include/id_printing.h
@@ -85,8 +85,7 @@ void deleteIds(CGAL::Three::Viewer_interface* viewer,
                TextListItem* vitems,
                TextListItem* eitems,
                TextListItem* fitems,
-               std::vector<TextItem*>* targeted_ids,
-               bool *all_primitives_displayed)
+               std::vector<TextItem*>* targeted_ids)
 {
   TextRenderer *renderer = viewer->textRenderer();
   BOOST_FOREACH(TextItem* it, vitems->textList())
@@ -102,7 +101,6 @@ void deleteIds(CGAL::Three::Viewer_interface* viewer,
   fitems->clear();
   renderer->removeTextList(fitems);
   targeted_ids->clear();
-  *all_primitives_displayed = false;
   viewer->update();
 }
 
@@ -175,8 +173,7 @@ void compute_displayed_ids(Mesh& mesh,
                            TextListItem* vitems,
                            TextListItem* eitems,
                            TextListItem* fitems,
-                           std::vector<TextItem*>* targeted_ids,
-                           bool *all_primitives_displayed)
+                           std::vector<TextItem*>* targeted_ids)
 {
   typedef typename boost::graph_traits<Mesh>::face_descriptor face_descriptor;
   typedef typename boost::graph_traits<Mesh>::vertex_descriptor vertex_descriptor;
@@ -228,11 +225,11 @@ void compute_displayed_ids(Mesh& mesh,
     if(text_item->position() == point)
     {
       //hide and stop
-      deleteIds(viewer, vitems, eitems, fitems, targeted_ids, all_primitives_displayed);
+      deleteIds(viewer, vitems, eitems, fitems, targeted_ids);
       return;
     }
   }
-  deleteIds(viewer, vitems, eitems, fitems, targeted_ids, all_primitives_displayed);
+  deleteIds(viewer, vitems, eitems, fitems, targeted_ids);
   // test the midpoint of edges of the closest face
   BOOST_FOREACH(halfedge_descriptor e, halfedges_around_face(halfedge(selected_fh, mesh), mesh))
   {
diff --git a/Polyhedron/demo/Polyhedron/resources/help_button.png b/Polyhedron/demo/Polyhedron/resources/help_button.png
new file mode 100644
index 00000000000..0c3d144072d
Binary files /dev/null and b/Polyhedron/demo/Polyhedron/resources/help_button.png differ
diff --git a/Three/include/CGAL/Three/Scene_group_item.h b/Three/include/CGAL/Three/Scene_group_item.h
index 91381e75d41..7cb47523bc3 100644
--- a/Three/include/CGAL/Three/Scene_group_item.h
+++ b/Three/include/CGAL/Three/Scene_group_item.h
@@ -175,6 +175,15 @@ public :
     //! Only returns children that have this item as a parent.
     //! Children of these children are not returned.
     QList<Scene_item*> getChildren() const {return children;}
+
+    //! \brief getChildrenForSelection returns the list of
+    //! children to select along with the group.
+    //!
+    //! When a `Scene_group_item` is added to the selection of the scene,
+    //! this function defines which of its children will be added too.
+    //! Typically overriden to allow applying an operation from the
+    //! Operation menu only to the parent item and not to its children.
+    virtual QList<Scene_item*> getChildrenForSelection() const {return children;}
     //!Removes a Scene_item from the list of children.
     //!@see getChildren() @see addChild()
     void removeChild( Scene_item* item)