Document interaction between native and React events

Closes: reactjs#68

content/docs/handling-events.md

@@ -58,6 +58,10 @@ Here, `e` is a synthetic event. React defines these synthetic events according t
 
 When using React you should generally not need to call `addEventListener` to add listeners to a DOM element after it is created. Instead, just provide a listener when the element is initially rendered.
 
+> Note:
+>
+> For performance reasons, React events are not guaranteed to be installed on the element they are created on. This means that using `stopPropagation` from event handlers installed outside of React might not be able to stop React events from occurring and vice versa. 
+
 When you define a component using an [ES6 class](https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Classes), a common pattern is for an event handler to be a method on the class. For example, this `Toggle` component renders a button that lets the user toggle between "ON" and "OFF" states:
 
 ```js{6,7,10-14,18}

content/docs/reference-events.md

@@ -35,6 +35,10 @@ string type
 >
 > As of v0.14, returning `false` from an event handler will no longer stop event propagation. Instead, `e.stopPropagation()` or `e.preventDefault()` should be triggered manually, as appropriate.
 
+> Note:
+>
+> Do not try to stop the execution of React events from native event handlers using `e.stopPropagation()` or vice versa. React events are not necessarily installed on the DOM element they are created on.
+
 ### Event Pooling
 
 The `SyntheticEvent` is pooled. This means that the `SyntheticEvent` object will be reused and all properties will be nullified after the event callback has been invoked.