Fix demo, note a caveat with body-attached elements

Author: simplesmiler

README.md

@@ -9,7 +9,7 @@
 Sometimes you need to detect clicks **outside** of the element (to close a modal
 window or hide a dropdown select). There is no native event for that, and Vue.js
 does not cover you either. This is why `vue-clickaway` exists. Please check out
-the [demo](https://jsfiddle.net/simplesmiler/4w1cs8u3/) before reading further.
+the [demo](https://jsfiddle.net/simplesmiler/4w1cs8u3/150/) before reading further.
 
 ## Requirements
 
@@ -78,7 +78,14 @@ export default {
 1. Pay attention to the letter case. `onClickaway` turns into `v-on-clickaway`,
    while `onClickAway` turns into `v-on-click-away`.
 2. Prior to `vue@^2.0`, directive were able to accept statements.
-   This is no longer the case.
+   This is no longer the case. If you need to pass arguments, just do
+   `v-on-clickaway="() => away(arg1)"`.
+3. There is a common issue with dropdowns (and modals) inside an element with
+   `v-on-clickaway`. Some UI libraries chose to implement these UI elements
+   by attaching the DOM element directly to the body. This makes clicks on
+   a dropped element trigger away handler. To combat that, you have to add
+   an extra check in the handler, for where the event originated from.
+   See #9 for an example.
 
 ## License