updating docs

README.md

@@ -648,6 +648,8 @@ It is recommended that you put a `min-height` on a vertical `Droppable` or a `mi
 
 ### Recommended `Droppable` performance optimisation
 
+> 📺 This optimisation is covered in a [free lesson of our getting started course](https://egghead.io/lessons/react-optimize-performance-in-react-beautiful-dnd-with-shouldcomponentupdate-and-purecomponent)
+
 When a user drags over, or stops dragging over, a `Droppable` we re-render the `Droppable` with an updated `DroppableStateSnapshot > isDraggingOver` value. This is useful for styling the `Droppable`. However, by default this will cause a render of all of the children of the `Droppable` - which might be 100's of `Draggable`s! This can result in a noticeable frame rate drop. To avoid this problem we recommend that you create a component that is the child of a `Droppable` who's responsibility it is to avoid rendering children if it is not required.
 
 Here is an example of how you could do this:
@@ -1181,10 +1183,11 @@ This codebase is designed to be **extremely performant** - it is part of its DNA
 
 - [Rethinking drag and drop](https://medium.com/@alexandereardon/rethinking-drag-and-drop-d9f5770b4e6b)
 - [Dragging React performance forward](https://medium.com/@alexandereardon/dragging-react-performance-forward-688b30d40a33)
+- [Grabbing the flame 🔥](https://medium.com/@alexandereardon/grabbing-the-flame-290c794fe852)
 
 ## Size
 
-Great care has been taken to keep the library as light as possible. It is currently **~38kb (gzip)** in size. There could be a smaller net cost if you where already using one of the underlying dependencies.
+Great care has been taken to keep the library as light as possible. It is currently **~31kb (gzip)** in size. There could be a smaller net cost if you where already using one of the underlying dependencies.
 
 ## Supported browsers
 

docs/guides/responders.md

@@ -215,17 +215,19 @@ Because this library does not control your state, it is up to you to _synchronou
 
 If you need to persist a reorder to a remote data store - update the list synchronously on the client (such as through `this.setState()`) and fire off a request in the background to persist the change. If the remote save fails it is up to you how to communicate that to the user and update, or not update, the list.
 
-## Block updates during a drag
+## No dimension changes during a drag
 
-It is **highly** recommended that while a user is dragging that you block any state updates that might impact the amount of `Draggable`s and `Droppable`s, or their dimensions. Please listen to `onDragStart` and block updates to the `Draggable`s and `Droppable`s until you receive at `onDragEnd`.
+`react-beautiful-dnd` does not support the changing of the size of any `Draggable` or `Droppable` after a drag has started. We build a virtual model of every `Draggable` and `Droppable` when a drag starts. We do not recollect these during a drag. So if you change the size of something: the user will see the updated size, but our virtual model will remain unchanged.
+
+### Block updates during a drag
 
-When the user starts dragging we take a snapshot of all of the dimensions of the applicable `Draggable` and `Droppable` nodes. If these change during a drag we will not know about it.
+It is **highly** recommended that while a user is dragging that you block any state updates that might impact the amount of `Draggable`s and `Droppable`s, or their dimensions. Please listen to `onDragStart` and block updates to the `Draggable`s and `Droppable`s until you receive at `onDragEnd`.
 
 ### How do you block updates?
 
 Update blocking will look different depending on how you manage your data. It is probably best to explain by example:
 
-Let's say you are using React component state to manage the state of your application. Your application state is tied to a REST endpoint that you poll every thirty seconds for data updates. During a drag you should not apply any server updates that could effect what is visible.
+Let's say you are using `React` component state to manage the state of your application. Your application state is tied to a REST endpoint that you poll every thirty seconds for data updates. During a drag you _should not_ apply any server updates that could effect what is visible.
 
 This could mean: