diff --git a/TODO.md b/TODO.md
index 41184b93..e15ef19e 100644
--- a/TODO.md
+++ b/TODO.md
@@ -173,3 +173,5 @@ function: ide_editor_map_bin_add()
 
 - Mouse ClickLock: do we need to do anything special? *should* we? https://msdn.microsoft.com/en-us/library/windows/desktop/ms724947(v=vs.85).aspx
 - consider a uiAnticipateDoubleClick() or uiDoubleClickTime() (for a uiQueueTimer()) or something: https://blogs.msdn.microsoft.com/oldnewthing/20041015-00/?p=37553
+
+- determine whether MSGF_USER is for and if it's correct for our uiArea message filter (if we have one)