diff --git a/todo.md b/todo.md
index ccc417c..8ead8cc 100644
--- a/todo.md
+++ b/todo.md
@@ -14,6 +14,7 @@ super ultra important things:
 	- will need old and new Mac keyboards...
 - make sure MouseEvent's documentation has dragging described correctly (both Windows and GTK+ do)
 	- fix OS X so that it follows these rules
+	- native Windows (not wine) and OS X don't respond to mouse button 4 and 5 drags?!
 - cap click count to 2 on all platforms
 - the windows build appears to be unstable:
 	- 64-bit crashes in malloc in wine with heap corruption warnings aplenty during DLL loading; in windows 7 it works fine