Fix updateGL() bugs

Polyhedron/demo/Polyhedron/MainWindow.h

@@ -246,7 +246,7 @@ protected Q_SLOTS:
    //!and viewer accordingly.
   /*!
    * Set the scene selected item or selected item list. Sets the manipulated
-   * frame of the viewer to the new selected item's and calls updateGL().
+   * frame of the viewer to the new selected item's and calls update().
    */
   void selectionChanged();
   //! Scrolls to the new selected item from its name in the Geometric Objects list.

Polyhedron/demo/Polyhedron/Plugins/Operations_on_polyhedra/Clip_polyhedron_plugin.cpp

@@ -243,7 +243,7 @@ public Q_SLOTS:
                                                 ui_widget.close_checkBox->isChecked());
           }
           item->invalidateOpenGLBuffers();
-          viewer->updateGL();
+          viewer->update();
         }
         else
         {