fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! fixup! Introduce custom design of FileInputField (#244)

Author: adamkudrna

src/components/FileInputField/README.md

@@ -179,7 +179,9 @@ It's possible to disable the whole input.
 ## Handling Files
 
 Files selected by the user can be handled by providing a custom function to the
-`onFilesChanged` prop.
+`onFilesChanged` prop. The `onFilesChanged` function is then called on the
+`change` event of the `input` element and on the `drop` event of the root
+`div` element.
 
 ```docoff-react-preview
 <FileInputField