diff --git a/COMPOSITE_TODO b/COMPOSITE_TODO
index 47efe8fa43..351288ebfe 100644
--- a/COMPOSITE_TODO
+++ b/COMPOSITE_TODO
@@ -143,6 +143,9 @@ OpenGL TODO
         obscured (makes a difference with many windows open)
     - http://lists.kde.org/?l=kwin&m=116585618111882&w=2
 
++ shm mode needs support for more data formats than GL_BGRA in order to support e.g. 16bpp mode
+    - http://www.xfree86.org/current/glTexImage2D.3.html
+
 
 XRender TODO
 ==============================
diff --git a/scene_opengl.cpp b/scene_opengl.cpp
index 181b7a251d..99949364ce 100644
--- a/scene_opengl.cpp
+++ b/scene_opengl.cpp
@@ -20,7 +20,7 @@ Sources and other compositing managers:
 
 - http://opengl.org
     - documentation
-        - OpenGL Redbook (http://opengl.org/documentation/red_book/)
+        - OpenGL Redbook (http://opengl.org/documentation/red_book/ - note it's only version 1.1)
         - GLX docs (http://opengl.org/documentation/specs/glx/glx1.4.pdf)
         - extensions docs (http://www.opengl.org/registry/)