diff --git a/src/OpenMesh/Apps/Decimating/decimaterviewer.cc b/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
index 5edaf767..da5a22db 100644
--- a/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
+++ b/src/OpenMesh/Apps/Decimating/decimaterviewer.cc
@@ -63,7 +63,6 @@ int main(int argc, char **argv)
 #endif
   
   // OpenGL check
-  QApplication::setColorSpec( QApplication::CustomColor );
   QApplication app(argc,argv);
   
   if ( !QGLFormat::hasOpenGL() ) {
diff --git a/src/OpenMesh/Apps/ProgViewer/progviewer.cc b/src/OpenMesh/Apps/ProgViewer/progviewer.cc
index 6f8eebc5..4ce5de6b 100644
--- a/src/OpenMesh/Apps/ProgViewer/progviewer.cc
+++ b/src/OpenMesh/Apps/ProgViewer/progviewer.cc
@@ -57,7 +57,6 @@
 int main(int argc, char **argv)
 {
   // OpenGL check
-  QApplication::setColorSpec( QApplication::CustomColor );
   QApplication app(argc,argv);
 
   if ( !QGLFormat::hasOpenGL() ) {
@@ -67,7 +66,7 @@ int main(int argc, char **argv)
 
     
   // create widget
-  ProgViewerWidget w(0);
+  ProgViewerWidget w(nullptr);
   w.resize(400, 400);
   w.show();
   
diff --git a/src/OpenMesh/Apps/QtViewer/meshviewer.cc b/src/OpenMesh/Apps/QtViewer/meshviewer.cc
index a3649154..fdb5c144 100644
--- a/src/OpenMesh/Apps/QtViewer/meshviewer.cc
+++ b/src/OpenMesh/Apps/QtViewer/meshviewer.cc
@@ -60,12 +60,11 @@ void usage_and_exit(int xcode);
 int main(int argc, char **argv)
 {
   // OpenGL check
-  QApplication::setColorSpec( QApplication::CustomColor );
   QApplication app(argc,argv);
 
   if ( !QGLFormat::hasOpenGL() ) {
     QString msg = "System has no OpenGL support!";
-    QMessageBox::critical( 0, QString("OpenGL"), msg + QString(argv[1]) );
+    QMessageBox::critical( nullptr, QString("OpenGL"), msg + QString(argv[1]) );
     return -1;
   }
 
diff --git a/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc b/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
index 665274dc..9421653b 100644
--- a/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
+++ b/src/OpenMesh/Apps/Subdivider/qtsubdivider.cc
@@ -55,7 +55,6 @@
 int main(int argc, char **argv)
 {
   // OpenGL check
-  QApplication::setColorSpec( QApplication::CustomColor );
   QApplication app(argc,argv);
 
   if ( !QGLFormat::hasOpenGL() ) {
@@ -66,7 +65,7 @@ int main(int argc, char **argv)
 
     
   // create widget
-  SubdivideWidget* w = new SubdivideWidget(0, "Subdivider");  
+  SubdivideWidget* w = new SubdivideWidget(nullptr, "Subdivider");
 
   w->resize(400, 400);
   w->show();
diff --git a/src/OpenMesh/Apps/VDProgMesh/Synthesizer/vdpmsynthesizer.cc b/src/OpenMesh/Apps/VDProgMesh/Synthesizer/vdpmsynthesizer.cc
index d4c11fcd..a46e8a19 100644
--- a/src/OpenMesh/Apps/VDProgMesh/Synthesizer/vdpmsynthesizer.cc
+++ b/src/OpenMesh/Apps/VDProgMesh/Synthesizer/vdpmsynthesizer.cc
@@ -55,7 +55,6 @@
 int main(int argc, char **argv)
 {
   // OpenGL check
-  QApplication::setColorSpec( QApplication::CustomColor );
   QApplication app(argc,argv);
 
 
@@ -66,7 +65,7 @@ int main(int argc, char **argv)
 
   // create widget
   VDPMSynthesizerViewerWidget* 
-    w = new VDPMSynthesizerViewerWidget(0, "VDPMSynthesizerViewer");
+  w = new VDPMSynthesizerViewerWidget(nullptr, "VDPMSynthesizerViewer");
 
   w->resize(400, 400);
   w->show();