diff --git a/todo.md b/todo.md
index 7a4c71c..9e54ea3 100644
--- a/todo.md
+++ b/todo.md
@@ -23,6 +23,7 @@ so I don't forget:
 	- will probably want to bring back Event() for this (but as NewEvent())
 - add bounds checking to Area's sizing methods
 - describe thread-safety of Area.SetSize()
+- should all instances of -1 as error returns from Windows functions be changed to ^0 or does the uintptr() conversion handle sign extension?
 
 important things:
 - because the main event loop is not called if initialization fails, it is presently impossible for MsgBoxError() to work if UI initialization fails; this basically means we cannot allow initializiation to fail on Mac OS X if we want to be able to report UI init failures to the user with one (which would be desirable, maybe (would violate Windows HIG?))