functional components invisible in devtools (vuejs#822)

Author: stevekrouse

src/v2/guide/render-function.md

@@ -478,7 +478,9 @@ Everything the component needs is passed through `context`, which is an object c
 
 After adding `functional: true`, updating the render function of our anchored heading component would simply require adding the `context` argument, updating `this.$slots.default` to `context.children`, then updating `this.level` to `context.props.level`.
 
-Since functional components are just functions, they're much cheaper to render. They're also very useful as wrapper components. For example, when you need to:
+Since functional components are just functions, they're much cheaper to render. However, this also mean that functional components don't show up in VueJS Chrome dev tools component tree.
+
+They're also very useful as wrapper components.  For example, when you need to:
 
 - Programmatically choose one of several other components to delegate to
 - Manipulate children, props, or data before passing them on to a child component