Great article. One thing I would like to mention is that using component state (this.setState) is okay! Central stores, and the flux architecture, are very helpful but if your state shouldn't persist after an unmount, there's no point in extracting to a central store and passing it through your entire app as props. (i.e. Whether or not a certain dropdown is expanded). Just keep that state local.
My point was that the state of the dropdown is something that perfectly fine to manage directly in the component (nothing else needs to know about it). Things like the selected value would not be something to manage using component state.
