Using IE 11 if one has an input component with a placeholder attribute and an onChange handler, the onChange handler will be called when clicking the input without typing anything in, just clicking it.
I made a reproducible case in codepen here: http://codepen.io/anon/pen/BoGQyZ If one opens it in IE and look in the console and clicks the input with the placeholder they should see an event from the onChange handler.
It seems to be a known issue that Microsoft is unwilling to fix. However if one of React's goals is to normalize the onChange event as the documentation implies this needs a workaround. One possible solution would be to check if the input that triggered an input event is focused at the moment.