Index: Rendering/vtkOpenGLRenderWindow.cxx
===================================================================
RCS file: /cvsroot/VTK/VTK/Rendering/vtkOpenGLRenderWindow.cxx,v
retrieving revision 1.97
diff -u -r1.97 vtkOpenGLRenderWindow.cxx
--- Rendering/vtkOpenGLRenderWindow.cxx	17 Jun 2008 15:53:12 -0000	1.97
+++ Rendering/vtkOpenGLRenderWindow.cxx	25 Jun 2008 08:13:30 -0000
@@ -1209,6 +1209,9 @@
   int     x_low, x_hi;
   int     width, height;
 
+  // Disable writing on the z-buffer.
+  glDepthMask(GL_FALSE);
+  glDisable(GL_DEPTH_TEST);
 
   // set the current window
   this->MakeCurrent();
@@ -1295,6 +1298,10 @@
                   data);
     }
 
+ // Disable writing on the z-buffer.
+  glDepthMask(GL_TRUE);
+  glEnable(GL_DEPTH_TEST);
+
   // This seems to be necessary for the image to show up
   glFlush();