diff --git a/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp b/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
index e7f2ef0f041..f96a5f64276 100644
--- a/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
+++ b/GraphicsView/demo/Bounding_volumes/Bounding_volumes.cpp
@@ -108,7 +108,7 @@ public slots:
 
   void on_actionRecenter_triggered();
 
-  void open(const QString& fileName);
+  virtual void open(QString fileName);
 
 signals:
   void changed();
@@ -479,7 +479,7 @@ MainWindow::on_actionLoadPoints_triggered()
 
 
 void
-MainWindow::open(const QString& fileName)
+MainWindow::open(QString fileName)
 {
   // wait cursor
   QApplication::setOverrideCursor(Qt::WaitCursor);
diff --git a/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp b/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
index d504f1b0ce6..c31b8452c4c 100644
--- a/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
+++ b/GraphicsView/demo/Circular_kernel_2/Circular_kernel_2.cpp
@@ -65,7 +65,7 @@ public:
 
 public slots:
 
-  void open(const QString&);
+  virtual void open(QString);
 
   void processInput(CGAL::Object o);
 
@@ -221,7 +221,7 @@ MainWindow::on_actionLoadLineAndCircularArcs_triggered()
 
 
 void
-MainWindow::open(const QString& fileName)
+MainWindow::open(QString fileName)
 {
     std::ifstream ifs(qPrintable(fileName));
     char c;