portals4.js

const App = () => {
  const [isOn, setOn] = useState(false);

  return <div style={{overflow: "hidden"}}>
      <Button onClick={e => {setOn(!isOn)}} >
        Click me
      </Button>
      {
        isOn &&
        <Portal>
          <Tooltip>
            <div>This tooltip will not cut off!</div>
          </Tooltip>
        </Portal>
      }
  </div>
}