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.

domElement: Element,
  updatePayload: Array<any>,
  wasCustomComponentTag: boolean,
  isCustomComponentTag: boolean,
): void {
  
  for (var i = 0; i < updatePayload.length; i += 2) {
    var propKey = updatePayload[i];
    var propValue = updatePayload[i + 1];
    if (propKey === STYLE) {
      
      CSSPropertyOperations.setValueForStyles(domElement, propValue);
    } else if (propKey === DANGEROUSLY_SET_INNER_HTML) {
      setInnerHTML(domElement, propValue);
    } else if (propKey === CHILDREN) {