Update CHANGELOG.md

Co-Authored-By: Chris Parmer <[email protected]>

Author: alexcjohnson

CHANGELOG.md

@@ -4,7 +4,7 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 ### Changed
-- [#740](https://github.com/plotly/dash-core-components/pull/740) Keep components that are loading in the DOM, but not visible, as opposed to removing them entirely
+- [#740](https://github.com/plotly/dash-core-components/pull/740) Keep components that are loading in the DOM, but not visible, as opposed to removing them entirely. This will ensure that the size of the component's container does not shrink or expand when the component goes into the loading state.
 
 ### Fixed
 - [#740](https://github.com/plotly/dash-core-components/pull/740) Fixed bug in which mapbox `uirevision` was not behaving when inside a `dcc.Loading` component