Reactjs 如何使用 MaterialUI 在 Appbar 下方打开下拉菜单

我对Material UI不太熟悉，刚开始摆弄他们的App bar with Menu example.切换菜单下拉菜单时，它会在应用程序栏上方打开，而我希望它在导航栏下方打开.

从文档中，我了解到这可以用anchorEl来完成，正如here所解释的那样.但当我把这个应用到menu组件时，什么都没发生.什么是"正确的material UI方式"来解决这个问题？

class Header extends React.Component {
  state = {
    auth: true,
    anchorEl: null,
    anchorOriginVertical: 'bottom',
    anchorOriginHorizontal: 'right',
    transformOriginVertical: 'top',
    transformOriginHorizontal: 'right',
    anchorReference: 'anchorEl',
  };

  handleChange = (event, checked) => {
    this.setState({ auth: checked });
  };

  handleMenu = event => {
    this.setState({ anchorEl: event.currentTarget });
  };

  handleClose = () => {
    this.setState({ anchorEl: null });
  };

  render() {
    const { classes } = this.props;
    const { auth, anchorEl } = this.state;
    const open = Boolean(anchorEl);

    return (
      <div className={classes.root}>
        <AppBar position="static">
          <Toolbar>
            <Typography type="title" color="inherit" className={classes.flex}>
              Title
            </Typography>
            {auth && (
              <div>
                <IconButton
                  aria-owns={open ? 'menu-appbar' : null}
                  aria-haspopup="true"
                  onClick={this.handleMenu}
                  color="contrast"
                >
                  <AccountCircle />
                </IconButton>
                <Menu
                  id="menu-appbar"
                  anchorEl={anchorEl}
                  open={open}
                  onClose={this.handleClose}
                >
                  <MenuItem onClick={this.handleClose}>Profile</MenuItem>
                  <MenuItem onClick={this.handleClose}>My account</MenuItem>
                </Menu>
              </div>
            )}
          </Toolbar>
        </AppBar>
      </div>
    );
  }
}