diff --git a/Doc/TODO b/Doc/TODO
index 69c61f7..32a318d 100644
--- a/Doc/TODO
+++ b/Doc/TODO
@@ -35,3 +35,6 @@
   fixing.)
 
 * Figure out HTMLHelp generation for the Windows world.
+
+* Before next Python release, document that the mode parameter to
+  wave.open() may be omitted, and how it is determined if omitted.