added ftransform() comment
diff --git a/docs/shading.html b/docs/shading.html
index ef54666..4e8f186 100644
--- a/docs/shading.html
+++ b/docs/shading.html
@@ -66,6 +66,8 @@
 <li>Shader error detection and reporting of errors (InfoLog) is not
     very good yet.
 <li>There are known memory leaks in the compiler.
+<li>The ftransform() function doesn't necessarily match the results of
+    fixed-function transformation.
 </ul>
 
 <p>