Material-UI Popover component does trigger onClose event

I am using Material-ui Popover component, the open of Popover component is handled by its state, I defined a function named handlePopoverClose to handle When I click outside the 'Hover with a Popover', it was supposed to set the state of anchorEl to null, and then state of open should turn to false. But this function action didn't trigger, does anyone know what happen?

import React from 'react';
import Popover from '@material-ui/core/Popover';
import Typography from '@material-ui/core/Typography';
import { makeStyles } from '@material-ui/core/styles';

const useStyles = makeStyles(theme => ({
  popover: {
    pointerEvents: 'none',
  },
  paper: {
    padding: theme.spacing(1),
  },
}));

export default function MouseOverPopover() {
  const classes = useStyles();
  const [anchorEl, setAnchorEl] = React.useState(null);

  const handlePopoverOpen = event => {
    setAnchorEl(event.currentTarget);
  };

  const handlePopoverClose = () => {
    setAnchorEl(null);
  };

  const open = Boolean(anchorEl);

  return (
    <div>
      <Typography
        aria-owns={open ? 'mouse-over-popover' : undefined}
        aria-haspopup="true"
        onMouseEnter={handlePopoverOpen}
      >
        Hover with a Popover.
      </Typography>
      <Popover
        id="mouse-over-popover"
        className={classes.popover}
        classes={{
          paper: classes.paper,
        }}
        open={open}
        anchorEl={anchorEl}
        anchorOrigin={{
          vertical: 'bottom',
          horizontal: 'left',
        }}
        transformOrigin={{
          vertical: 'top',
          horizontal: 'left',
        }}
        onClose={handlePopoverClose}
        disableRestoreFocus
      >
        <Typography>I use Popover.</Typography>
      </Popover>
    </div>
  );
}