diff --git a/src/doc/sx.rst b/src/doc/sx.rst
index 5b89bd7239..9866f49011 100644
--- a/src/doc/sx.rst
+++ b/src/doc/sx.rst
@@ -24,6 +24,7 @@ TODO
   - [x] move files around
   - [ ] GncSxListTreeModelAdapter: s/real/adapted/
   - [ ] generic tree model adapter setup code
+  - [ ] move documentation into doxygen comments, here and in sources.
 
 - core
   - [x] sx list -> qof collection