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.

case 'input':
        lastProps = ReactDOMInput.getHostProps(this, lastProps);
        nextProps = ReactDOMInput.getHostProps(this, nextProps);
        break;
      case 'option':
        lastProps = ReactDOMOption.getHostProps(this, lastProps);
        nextProps = ReactDOMOption.getHostProps(this, nextProps);
        break;
      case 'select':
        lastProps = ReactDOMSelect.getHostProps(this, lastProps);
        nextProps = ReactDOMSelect.getHostProps(this, nextProps);
        break;
      case 'textarea':
        lastProps = ReactDOMTextarea.getHostProps(this, lastProps);
        nextProps = ReactDOMTextarea.getHostProps(this, nextProps);
        break;
      default:
        if (
          typeof lastProps.onClick !== 'function' &&
          typeof nextProps.onClick === 'function'
        ) {
          transaction
            .getReactMountReady()
            .enqueue(trapClickOnNonInteractiveElement, this);
        }
        break;
    }
    assertValidProps(this, nextProps);
    var isCustomComponentTag = isCustomComponent(this._tag, nextProps);
    this._updateDOMProperties(