diff --git a/Polyhedron/demo/Polyhedron/MainWindow.cpp b/Polyhedron/demo/Polyhedron/MainWindow.cpp
index 6f9073421dd..6866f6ef032 100644
--- a/Polyhedron/demo/Polyhedron/MainWindow.cpp
+++ b/Polyhedron/demo/Polyhedron/MainWindow.cpp
@@ -1323,6 +1323,8 @@ void MainWindow::selectSceneItem(int i)
   else {
     QItemSelection s =
         proxyModel->mapSelectionFromSource(scene->createSelection(i));
+    if(s.empty())
+      return;
     QModelIndex mi = proxyModel->mapFromSource(scene->getModelIndexFromId(i).first());
     sceneView->setCurrentIndex(mi);
     sceneView->selectionModel()->select(s,
@@ -1347,7 +1349,8 @@ void MainWindow::selectSceneItems(QList<int> is)
     sceneView->setCurrentIndex(i);
     sceneView->selectionModel()->select(s,
                                         QItemSelectionModel::ClearAndSelect);
-    sceneView->scrollTo(s.indexes().first());
+    if(!s.empty())
+      sceneView->scrollTo(s.indexes().first());
   }
 }
 
@@ -1392,10 +1395,7 @@ void MainWindow::removeSceneItemFromSelection(int i)
 
 void MainWindow::selectAll()
 {
-  QItemSelection s =
-      proxyModel->mapSelectionFromSource(scene->createSelectionAll());
-  sceneView->selectionModel()->select(s,
-                                      QItemSelectionModel::ClearAndSelect);
+  sceneView->selectAll();
 }
 
 int MainWindow::getSelectedSceneItemIndex() const
@@ -1789,12 +1789,12 @@ void MainWindow::updateInfo() {
     CGAL::Bbox_3 bbox = item->bbox();
     if(bbox !=CGAL::Bbox_3())
       item_text += QString("<div>Bounding box: min (%1,%2,%3), max (%4,%5,%6)</div>")
-          .arg(bbox.xmin())
-          .arg(bbox.ymin())
-          .arg(bbox.zmin())
-          .arg(bbox.xmax())
-          .arg(bbox.ymax())
-          .arg(bbox.zmax());
+          .arg(bbox.xmin(),0, 'g', 17)
+          .arg(bbox.ymin(),0, 'g', 17)
+          .arg(bbox.zmin(),0, 'g', 17)
+          .arg(bbox.xmax(),0, 'g', 17)
+          .arg(bbox.ymax(),0, 'g', 17)
+          .arg(bbox.zmax(),0, 'g', 17);
     if(!item_filename.isEmpty()) {
       item_text += QString("<div>File:<i> %1</div>").arg(item_filename);
     }
diff --git a/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
index 4a99a1101c0..75b996dda51 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/PCA/Affine_transform_plugin.cpp
@@ -450,7 +450,7 @@ void Polyhedron_demo_affine_transform_plugin::grid()
             Kernel::Aff_transformation_3 trans(CGAL::TRANSLATION, Kernel::Vector_3(i*x_t,j*y_t,k*z_t));
             CGAL::Polygon_mesh_processing::transform(trans, e);
             Facegraph_item* t_item = new Facegraph_item(e);
-            t_item->setName(tr("%1 %2%3%4")
+            t_item->setName(tr("%1 %2,%3,%4")
                             .arg(item->name())
                             .arg(i)
                             .arg(j)
diff --git a/Polyhedron/demo/Polyhedron/Scene.cpp b/Polyhedron/demo/Polyhedron/Scene.cpp
index 2fcc276a1ce..8ea8f34d521 100644
--- a/Polyhedron/demo/Polyhedron/Scene.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene.cpp
@@ -704,7 +704,22 @@ Scene::draw_aux(bool with_names, CGAL::Three::Viewer_interface* viewer)
     Q_FOREACH(Item_id id, children)
     {
       Scene_item* item = m_entries[id];
-      if(item->alpha() == 1.0f)
+      Scene_group_item* group = qobject_cast<Scene_group_item*>(item);
+      bool is_transparent=false;
+      if(item->alpha() != 1.0f)
+        is_transparent = true;
+      else if(group)
+      {
+        for(const auto& child : group->getChildren())
+        {
+          if(group->getChild(child)->alpha() < 1.0f)
+          {
+            is_transparent = true;
+            break;
+          }
+        }
+      }
+      if(!is_transparent)
         opaque_items.push_back(id);
       else
         transparent_items.push_back(id);
@@ -1200,6 +1215,8 @@ bool Scene::sort_lists(QVector<QList<int> >&sorted_lists, bool up)
 }
 void Scene::moveRowUp()
 {
+  if(selectionIndices().isEmpty())
+    return;
   QVector<QList<int> >sorted_lists(1);
   QList<int> to_select;
   //sort lists according to the indices of each item in its container (scene or group)
@@ -1251,6 +1268,8 @@ void Scene::moveRowUp()
 }
 void Scene::moveRowDown()
 {
+  if(selectionIndices().isEmpty())
+    return;
   QVector<QList<int> >sorted_lists(1);
   QList<int> to_select;
   //sort lists according to the indices of each item in its container (scene or group)
@@ -1300,7 +1319,9 @@ void Scene::moveRowDown()
       }
     }
   }
-  selectionChanged(to_select);
+  if(!to_select.isEmpty()){
+    selectionChanged(to_select);
+  }
 }
 Scene::Item_id Scene::mainSelectionIndex() const {
     return (selectionIndices().size() == 1) ? selected_item : -1;
diff --git a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
index f350e500775..ed1fd56a3ec 100644
--- a/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_c3t3_item.cpp
@@ -153,7 +153,7 @@ public :
       alphaSlider->setMaximum(255);
       alphaSlider->setValue(255);
     }
-    viewer->makeCurrent();
+    //viewer->makeCurrent();
     const EPICK::Plane_3& plane = qobject_cast<Scene_c3t3_item*>(this->parent())->plane();
     float shrink_factor = qobject_cast<Scene_c3t3_item*>(this->parent())->getShrinkFactor();
     QVector4D cp = cgal_plane_to_vector4d(plane);
diff --git a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.cpp
index e4d61b95ef9..952c845aa55 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.cpp
@@ -546,12 +546,14 @@ Scene_polygon_soup_item::draw(CGAL::Three::Viewer_interface* viewer) const {
 
       if(d->soup->fcolors.empty())
         getTriangleContainer(Priv::Flat_facets)->setColor(this->color());
+      getTriangleContainer(Priv::Flat_facets)->setAlpha(alpha());
       getTriangleContainer(Priv::Flat_facets)->draw(viewer, d->soup->fcolors.empty());
     }
     else if(renderingMode() == Gouraud)
     {
       if(d->soup->vcolors.empty())
         getTriangleContainer(Priv::Smooth_facets)->setColor(this->color());
+      getTriangleContainer(Priv::Smooth_facets)->setAlpha(alpha());
       getTriangleContainer(Priv::Smooth_facets)->draw(viewer, d->soup->vcolors.empty());
     }
   }
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.cpp
index faae911f852..10b5b4e3fb8 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.cpp
@@ -2610,3 +2610,17 @@ CGAL::Three::Scene_item::Header_data Scene_polyhedron_selection_item::header() c
   data.titles.append(QString("Average"));
   return data;
 }
+
+
+void Scene_polyhedron_selection_item::updateDisplayedIds(QEvent* e)
+{
+  if(e->type() == QEvent::MouseButtonRelease )
+  {
+    QMouseEvent* mouse_event = static_cast<QMouseEvent*>(e);
+    if((mouse_event->button() == Qt::RightButton || mouse_event->button() == Qt::MiddleButton)
+       && temp_selected_vertices.size() == 1) {
+      fg_vertex_descriptor vh = *temp_selected_vertices.begin();
+      poly_item->updateIds(vh);
+    }
+  }
+}
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.h b/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.h
index 936152e5086..dbfca601296 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_selection_item.h
@@ -799,6 +799,7 @@ public:
   }
 
   void selection_changed(bool);
+  void updateDisplayedIds(QEvent *e);
 
 Q_SIGNALS:
   void updateInstructions(QString);
@@ -875,6 +876,8 @@ protected:
       }
     }
 
+    updateDisplayedIds(gen_event);
+
     if(!visible() || !k_ring_selector.state.shift_pressing) { return false; }
     if(gen_event->type() == QEvent::Wheel)
     {
diff --git a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
index 19e7013495b..af7964d3164 100644
--- a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.cpp
@@ -136,6 +136,7 @@ struct Scene_surface_mesh_item_priv{
                               << GouraudPlusEdges
                               << Points;
     item->setProperty("classname", QString("surface_mesh"));
+    ids_need_update = false;
   }
 
   Scene_surface_mesh_item_priv(SMesh* sm, Scene_surface_mesh_item *parent):
@@ -168,7 +169,8 @@ struct Scene_surface_mesh_item_priv{
                               << Gouraud
                                  << GouraudPlusEdges
                               << Points;
-    item->setProperty("classname", QString("surface_mesh"));
+    item->setProperty("classname", QString("surface_mesh"));\
+    ids_need_update = false;
   }
 
   ~Scene_surface_mesh_item_priv()
@@ -224,7 +226,6 @@ struct Scene_surface_mesh_item_priv{
   mutable bool edges_displayed;
   mutable bool faces_displayed;
   mutable bool all_displayed;
-  mutable QList<double> text_ids;
   mutable std::vector<TextItem*> targeted_id;
 
   std::string comments;
@@ -239,7 +240,6 @@ struct Scene_surface_mesh_item_priv{
   mutable bool isinit;
   mutable std::vector<unsigned int> idx_data_;
   mutable std::size_t idx_data_size;
-  mutable std::map<unsigned int, unsigned int> current_indices; //map im values to ghosts-free values
   mutable std::vector<unsigned int> idx_edge_data_;
   mutable std::size_t idx_edge_data_size;
   mutable std::vector<unsigned int> idx_feature_edge_data_;
@@ -267,6 +267,7 @@ struct Scene_surface_mesh_item_priv{
   bool has_nm_vertices;
   int genus;
   bool self_intersect;
+  bool ids_need_update;
   mutable QSlider* alphaSlider;
   QList<RenderingMode> supported_rendering_modes;
 };
@@ -2017,6 +2018,7 @@ void Scene_surface_mesh_item_priv::fillTargetedIds(const face_descriptor &select
                                                  CGAL::Three::Viewer_interface *viewer,
                                                  const CGAL::qglviewer::Vec& offset)
 {
+  all_displayed = false;
   compute_displayed_ids(*smesh_,
                         viewer,
                         selected_fh,
@@ -2368,9 +2370,31 @@ void Scene_surface_mesh_item::updateVertex(vertex_descriptor vh)
             getTriangleContainer(0)->getVbo(Tri::Smooth_normals),
             new_point,id);
     }
+    d->ids_need_update = true;
+    redraw();
+  }
+}
+
+void Scene_surface_mesh_item::updateIds(vertex_descriptor vh)
+{
+  if(d->ids_need_update &&
+     (d->faces_displayed || d->vertices_displayed || d->edges_displayed))
+  {
+    invalidate_aabb_tree();
+
+    if(d->all_displayed)
+    {
+      d->killIds();
+      d->all_displayed = true;
+      ::printVertexIds(*d->smesh_, d->textVItems);
+    }
+    else
+    {
+      d->fillTargetedIds(face(halfedge(vh, *d->smesh_), *d->smesh_),
+                         face_graph()->point(vh), CGAL::Three::Three::mainViewer(), CGAL::Three::Three::mainViewer()->offset());
+    }
+    d->ids_need_update = false;
   }
-  invalidate_aabb_tree();
-  redraw();
 }
 
 void Scene_surface_mesh_item::switchToGouraudPlusEdge(bool b)
diff --git a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.h b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.h
index ce3ea53002a..b8b88be572f 100644
--- a/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_surface_mesh_item.h
@@ -156,6 +156,7 @@ public:
   void computeElements() const Q_DECL_OVERRIDE;
   void initializeBuffers(CGAL::Three::Viewer_interface*)const Q_DECL_OVERRIDE;
   void updateVertex(vertex_descriptor vh);
+  void updateIds(vertex_descriptor vh);
   void switchToGouraudPlusEdge(bool b); //replace flatPlusEdge by gouraudPlusEdge and ban Flat.
 Q_SIGNALS:
   void item_is_about_to_be_changed();
diff --git a/Polyhedron/demo/Polyhedron/Viewer.cpp b/Polyhedron/demo/Polyhedron/Viewer.cpp
index 8c53251c18c..95ede4b08db 100644
--- a/Polyhedron/demo/Polyhedron/Viewer.cpp
+++ b/Polyhedron/demo/Polyhedron/Viewer.cpp
@@ -408,6 +408,7 @@ Viewer::~Viewer()
                              .arg(d->back_color.greenF())
                              .arg(d->back_color.blueF()));
 
+    d->vao.destroy();
     if(d->_recentFunctions)
       delete d->_recentFunctions;
     if(d->painter)
@@ -1559,12 +1560,18 @@ void Viewer_impl::showDistance(QPoint pixel)
         TextItem *ACoord = new TextItem(float(APoint.x),
                                         float(APoint.y),
                                         float(APoint.z),
-                                        QString("A(%1,%2,%3)").arg(APoint.x-viewer->offset().x).arg(APoint.y-viewer->offset().y).arg(APoint.z-viewer->offset().z), true, font, Qt::red, true);
+                                        QString("A(%1,%2,%3)")
+                                        .arg(APoint.x-viewer->offset().x, 0, 'g', 10)
+                                        .arg(APoint.y-viewer->offset().y, 0, 'g', 10)
+                                        .arg(APoint.z-viewer->offset().z, 0, 'g', 10), true, font, Qt::red, true);
         distance_text.append(ACoord);
         TextItem *BCoord = new TextItem(float(BPoint.x),
                                         float(BPoint.y),
                                         float(BPoint.z),
-                                        QString("B(%1,%2,%3)").arg(BPoint.x-viewer->offset().x).arg(BPoint.y-viewer->offset().y).arg(BPoint.z-viewer->offset().z), true, font, Qt::red, true);
+                                        QString("B(%1,%2,%3)")
+                                        .arg(BPoint.x-viewer->offset().x, 0, 'g', 10)
+                                        .arg(BPoint.y-viewer->offset().y, 0, 'g', 10)
+                                        .arg(BPoint.z-viewer->offset().z, 0, 'g', 10), true, font, Qt::red, true);
         distance_text.append(BCoord);
         CGAL::qglviewer::Vec centerPoint = 0.5*(BPoint+APoint);
         TextItem *centerCoord = new TextItem(float(centerPoint.x),
@@ -1582,7 +1589,7 @@ void Viewer_impl::showDistance(QPoint pixel)
                   .arg(BPoint.x-viewer->offset().x)
                   .arg(BPoint.y-viewer->offset().y)
                   .arg(BPoint.z-viewer->offset().z)
-                  .arg(dist)));
+                  .arg(dist, 0, 'g', 10)));
     }
 
 }
diff --git a/Three/include/CGAL/Three/Scene_draw_interface.h b/Three/include/CGAL/Three/Scene_draw_interface.h
index 3a77569d102..4ceaa728a23 100644
--- a/Three/include/CGAL/Three/Scene_draw_interface.h
+++ b/Three/include/CGAL/Three/Scene_draw_interface.h
@@ -16,6 +16,7 @@
 #include <CGAL/license/Three.h>
 
 #include <QPoint>
+#include <QVector3D>
 class QKeyEvent;
 class QPoint;
 namespace CGAL