This usually means that the user mixed up our lowercase/uppercase naming convention; see https://github.com/facebook/react/pull/3429#issuecomment-85166440.

We could add a message like

> Warning: The tag <commentBox> is unrecognized in this browser. If you meant to render a React component, start its name with an uppercase letter.

We'd check this only once per tag and only in development mode.

ReactBrowserEventEmitter.trapBubbledEvent('topInvalid', 'invalid', node);
      break;
    case 'details':
      ReactBrowserEventEmitter.trapBubbledEvent('topToggle', 'toggle', node);
      break;
  }
}
var omittedCloseTags = {
  area: true,
  base: true,
  br: true,
  col: true,
  embed: true,
  hr: true,
  img: true,
  input: true,
  keygen: true,
  link: true,
  meta: true,
  param: true,
  source: true,
  track: true,
  wbr: true,
  
};
var voidElementTags = {
  menuitem: true,
  ...omittedCloseTags,
};
function isCustomComponent(tagName, props) {