diff --git a/ImageShader.cpp b/ImageShader.cpp
index bfa7c0e..f9f9b7f 100644
--- a/ImageShader.cpp
+++ b/ImageShader.cpp
@@ -74,6 +74,6 @@ void ImageShader::operator = (const ImageShader &S )
 
 
 void ImageShader::accept(Visitor& v) {
-    Shader::accept(v);
+//    Shader::accept(v);
     v.visit(*this);
 }
diff --git a/Source.cpp b/Source.cpp
index 17dd08d..2739653 100644
--- a/Source.cpp
+++ b/Source.cpp
@@ -121,6 +121,7 @@ Source::Source() : initialized_(false), active_(true), need_update_(true)
 
     // those will be associated to nodes later
     blendingshader_ = new ImageShader;
+//    rendershader_   = new ImageShader;
     rendershader_   = new ImageProcessingShader;
     renderbuffer_   = nullptr;
     rendersurface_  = nullptr;
diff --git a/Source.h b/Source.h
index 7d78165..17e9723 100644
--- a/Source.h
+++ b/Source.h
@@ -63,6 +63,7 @@ public:
     bool contains (Node *node) const;
 
     // a Source has a shader to control image processing effects
+//    inline ImageShader *processingShader () const { return rendershader_; }
     inline ImageProcessingShader *processingShader () const { return rendershader_; }
 
     // a Source has a shader to control mixing effects
@@ -137,6 +138,7 @@ protected:
     FrameBufferSurface *rendersurface_;
 
     // rendershader performs image processing
+//    ImageShader *rendershader_;
     ImageProcessingShader *rendershader_;
 
     // blendingshader provides mixing controls