diff --git a/gl/inc/TGLUtil.h b/gl/inc/TGLUtil.h
index 3f3cbbee16eb12c4424dfad6f3faa33ad557cace..1d02294c34968991c4b2af49d0c4af847dd78f12 100644
--- a/gl/inc/TGLUtil.h
+++ b/gl/inc/TGLUtil.h
@@ -1,4 +1,4 @@
-// @(#)root/gl:$Name:  $:$Id: TGLUtil.h,v 1.29 2006/06/13 15:43:39 couet Exp $
+// @(#)root/gl:$Name:  $:$Id: TGLUtil.h,v 1.30 2006/08/31 13:42:14 couet Exp $
 // Author:  Richard Maunder  25/05/2005
 
 /*************************************************************************
@@ -827,6 +827,11 @@ class TGLUtil
 private:
    static UInt_t fgDrawQuality;
 
+protected:
+   TGLUtil(const TGLUtil&) {} // copy constructor
+   TGLUtil& operator=(const TGLUtil& glu) // assignment operator
+     {if(this!=&glu) {} return *this;}
+
 public:
    virtual ~TGLUtil() { }