diff --git a/NOTES_4_0 b/NOTES_4_0
index f4597ced0d..2e8286a719 100644
--- a/NOTES_4_0
+++ b/NOTES_4_0
@@ -89,6 +89,7 @@ There are more features that are not enabled by default and need to be explicitl
 in the configuration.
 
 XXX link to 4.0 kwin video
+XXX note the kwin_composite tag at youtube
 
 
 = Troubleshooting =