Keyboard event handlers no longer invoked if document.body get's focus.

[Gozala]

In my example app / root component is rendered into document.body it also set's up onKeyDown onKeyUp to handle application keyboard shortcuts.

The problem I'm running into is that some user interaction like clicking around page causes document.body to obtain focus (to become document.activeElement) and in that case onKeyDown & onKeyUp event handlers are no longer invoked.

I know I could register "keydown", "keyup" event handlers manually once app component is mounted but I would prefer to stay with-in react.

[syranide]

I'd call this a duplicate of #285, re-open if you disagree.