diff --git a/TODO.md b/TODO.md
index c721a1eb..3c969a7d 100644
--- a/TODO.md
+++ b/TODO.md
@@ -70,6 +70,7 @@ https://zhuanlan.zhihu.com/p/33778843
 - [ ] Demo: TextEditor
   - [ ] Use toolstrip group instead of splitter
   - [ ] Recently opened files in both menu and toolbar
+- [ ] Prevent from crashing while binding to a.b.c if a.b is null with a.b.cChanged exists
 - [ ] **Update Release**
 - [ ] Demo: TriplePhaseImageButton
   - [x] Add TemplateContext(Changed) property to both Control and Template