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.

.getReactMountReady()
            .enqueue(AutoFocusUtils.focusDOMComponent, this);
        }
        break;
      case 'button':
        if (props.autoFocus) {
          transaction
            .getReactMountReady()
            .enqueue(AutoFocusUtils.focusDOMComponent, this);
        }
        break;
      case 'option':
        transaction.getReactMountReady().enqueue(optionPostMount, this);
        break;
      default:
        if (typeof props.onClick === 'function') {
          transaction
            .getReactMountReady()
            .enqueue(trapClickOnNonInteractiveElement, this);
        }
        break;
    }
    return mountImage;
  },
  /**
   * Creates markup for the open tag and all attributes.
   *
   * This method has side effects because events get registered.
   *
   * Iterating over object properties is faster than iterating over arrays.