See the original report in https://github.com/facebook/react/issues/10772#issuecomment-333242375. The problem is that SVG is case sensitive, and so naïvely setting `tabIndex` and relying on insensitivity won't work with it. The good news is it seems like `tabindex` is the only valid [SVG attribute](https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute) with this problem. We just missed it because it applies both to HTML and SVG. I think the fix is to add it back to the whitelist.