diff --git a/docs/source/whatsnew/pr/incompat-deprecated-widget-names.rst b/docs/source/whatsnew/pr/incompat-deprecated-widget-names.rst
index 89a9c7d..6ccd7aa 100644
--- a/docs/source/whatsnew/pr/incompat-deprecated-widget-names.rst
+++ b/docs/source/whatsnew/pr/incompat-deprecated-widget-names.rst
@@ -1,3 +1,6 @@
 * The widget classes have been renamed from `*Widget` to `*`.  The old names are 
   still functional, but are deprecated.  i.e. `IntSliderWidget` has been renamed 
   to `IntSlider`.
+* The ContainerWidget was renamed to Box and no longer defaults as a flexible
+  box in the web browser.  A new FlexBox widget was added, which allows you to
+  use the flexible box model.