diff --git a/Polyhedron/demo/Polyhedron/Scene.cpp b/Polyhedron/demo/Polyhedron/Scene.cpp
index 8169c09e2c7..a56c0379d50 100644
--- a/Polyhedron/demo/Polyhedron/Scene.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene.cpp
@@ -112,6 +112,9 @@ Scene::erase(QList<int> indices)
   QAbstractListModel::reset();
 
   int index = max_index + 1 - indices.size();
+  if(index >= m_entries.size()) {
+    index = m_entries.size() - 1;
+  }
   if(index >= 0)
     return index;
   if(!m_entries.isEmpty())
diff --git a/Polyhedron/demo/Polyhedron/Scene_item_with_display_list.cpp b/Polyhedron/demo/Polyhedron/Scene_item_with_display_list.cpp
index f77c1574962..e8fbe7b9634 100644
--- a/Polyhedron/demo/Polyhedron/Scene_item_with_display_list.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_item_with_display_list.cpp
@@ -48,7 +48,7 @@ void Scene_item_with_display_list::draw(int i) const
       }
     }
     // draw the item in a display list
-    ::glNewList(display_list[i],GL_COMPILE_AND_EXECUTE);
+    ::glNewList(display_list[i],GL_COMPILE);
     if(i == 0) {
       direct_draw();
     }
@@ -56,6 +56,7 @@ void Scene_item_with_display_list::draw(int i) const
       direct_draw_edges();
     }
     ::glEndList();
+    ::glCallList(display_list[i]);
     display_list_built[i] = true;
   }
   else {
diff --git a/Polyhedron/demo/Polyhedron/Scene_nef_rendering.cpp b/Polyhedron/demo/Polyhedron/Scene_nef_rendering.cpp
index 987b0562897..fb0eef97656 100644
--- a/Polyhedron/demo/Polyhedron/Scene_nef_rendering.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_nef_rendering.cpp
@@ -168,6 +168,7 @@ void gl_render_nef_edges(Nef_polyhedron *p)
 	end = p->halfedges_end();
       e != end; ++e)
   {
+    if (e->is_twin()) continue;
     const Nef_polyhedron::Vertex_const_handle& s = e->source();
     const Nef_polyhedron::Vertex_const_handle& t = e->twin()->source();
     const Nef_polyhedron::Point_3& a = s->point();
diff --git a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.h b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.h
index 920fba0ce37..648056d1e3f 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.h
+++ b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item.h
@@ -10,7 +10,7 @@
 struct Polygon_soup;
 class Scene_polyhedron_item;
 
-class SCENE_POLYGON_SOUP_EXPORT Scene_polygon_soup_item 
+class SCENE_POLYGON_SOUP_ITEM_EXPORT Scene_polygon_soup_item 
   : public Scene_item_with_display_list 
 {
   Q_OBJECT
diff --git a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item_config.h b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item_config.h
index 6b8ce16ff7b..8d9ad15ad4f 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item_config.h
+++ b/Polyhedron/demo/Polyhedron/Scene_polygon_soup_item_config.h
@@ -2,9 +2,9 @@
 #define SCENE_POLYGON_SOUP_ITEM_CONFIG_H
 
 #ifdef scene_polygon_soup_item_EXPORTS
-#  define SCENE_POLYGON_SOUP_EXPORT Q_DECL_EXPORT
+#  define SCENE_POLYGON_SOUP_ITEM_EXPORT Q_DECL_EXPORT
 #else
-#  define SCENE_POLYGON_SOUP_EXPORT Q_DECL_IMPORT
+#  define SCENE_POLYGON_SOUP_ITEM_EXPORT Q_DECL_IMPORT
 #endif
 
 #endif // SCENE_POLYGON_SOUP_ITEM_CONFIG_H
diff --git a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
index 7009db4a32f..f40c83388b4 100644
--- a/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
+++ b/Polyhedron/demo/Polyhedron/Scene_polyhedron_item.cpp
@@ -377,6 +377,7 @@ Scene_polyhedron_item::select(double orig_x,
                 nearest_v = v;
               }
             }
+            std::cerr << "Selected vertex: " << v->point() << std::endl;
             emit selected_vertex((void*)(&*nearest_v));
           }
           
diff --git a/Polyhedron/demo/Polyhedron/Show_point_dialog.cpp b/Polyhedron/demo/Polyhedron/Show_point_dialog.cpp
index c0802a85457..8d4812cea12 100644
--- a/Polyhedron/demo/Polyhedron/Show_point_dialog.cpp
+++ b/Polyhedron/demo/Polyhedron/Show_point_dialog.cpp
@@ -1,6 +1,8 @@
 #include "Show_point_dialog.h"
 #include "ui_Show_point_dialog.h"
 
+#include <QClipboard>
+
 Show_point_dialog::Show_point_dialog(QWidget* parent)
   : QDialog(parent)
   , ui(new Ui::Show_point_dialog)
@@ -8,6 +10,22 @@ Show_point_dialog::Show_point_dialog(QWidget* parent)
 {
   ui->setupUi(this);
 
+  QClipboard::Mode mode = QClipboard::Selection; 
+  while(true) {
+    QString clipboard_text = QApplication::clipboard()->text(mode);
+    
+    interprete_string(clipboard_text);
+    if(m_has_correct_coordinates) {
+      ui->lineEdit->setText(clipboard_text);
+      ui->lineEdit->selectAll();
+      break;
+    } else {
+      interprete_string(ui->lineEdit->text());
+    }
+    if(mode == QClipboard::Selection) mode = QClipboard::Clipboard;
+    else break;
+  }
+
   connect(ui->lineEdit, SIGNAL(textChanged(const QString&)),
           this, SLOT(interprete_string(const QString&)));
 }
diff --git a/Polyhedron/demo/Polyhedron/Viewer.cpp b/Polyhedron/demo/Polyhedron/Viewer.cpp
index 7e388703e7f..ec36d1965b0 100644
--- a/Polyhedron/demo/Polyhedron/Viewer.cpp
+++ b/Polyhedron/demo/Polyhedron/Viewer.cpp
@@ -1,4 +1,6 @@
 #include "Viewer.h"
+#include <CGAL/gl.h>
+#include <CGAL/check_gl_error.h>
 #include "Scene_draw_interface.h"
 #include <QMouseEvent>
 #include <QKeyEvent>
@@ -168,14 +170,14 @@ void Viewer_impl::draw_aux(bool with_names)
   {
     ::glDisable(GL_BLEND);
     ::glDisable(GL_LINE_SMOOTH);
-    ::glDisable(GL_POLYGON_SMOOTH_HINT);
-    ::glBlendFunc(GL_ONE, GL_ZERO);
     ::glHint(GL_LINE_SMOOTH_HINT, GL_FASTEST);
+    ::glBlendFunc(GL_ONE, GL_ZERO);
   }
   if(with_names)
     scene->drawWithNames();
   else
     scene->draw();
+  CGAL::check_gl_error(__FILE__, __LINE__);
 }
 
 void Viewer::drawWithNames()
diff --git a/Polyhedron/demo/Polyhedron/include/CGAL/check_gl_error.h b/Polyhedron/demo/Polyhedron/include/CGAL/check_gl_error.h
new file mode 100644
index 00000000000..baf05b45e1c
--- /dev/null
+++ b/Polyhedron/demo/Polyhedron/include/CGAL/check_gl_error.h
@@ -0,0 +1,44 @@
+// Copyright (c) 2011 GeometryFactory, Sophia Antipolis (France)
+//  All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation; version 2.1 of the License.
+// See the file LICENSE.LGPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/next/Installation/include/CGAL/gl.h $
+// $Id: gl.h 45375 2008-09-08 11:40:39Z spion $
+//
+// Author: Laurent Rineau
+
+#ifndef CGAL_GL_CHECK_ERROR_H
+#define CGAL_GL_CHECK_ERROR_H
+
+#include <iostream>
+#include <CGAL/glu.h>
+
+namespace CGAL {
+
+inline void check_gl_error(const char* filename, long line)
+{
+  GLenum error = glGetError();
+  if(error != GL_NO_ERROR) {
+    std::cerr << "GL errors! file " << filename << ", line:" << line << "\n";
+    do {
+      std::cerr << gluErrorString(error) << std::endl;
+      error = glGetError();
+    }
+    while(error != GL_NO_ERROR);
+    std::cerr << "end of errors\n";
+  }
+}
+
+} // end namespace CGAL
+
+#endif // CGAL_GL_CHECK_ERROR_H