Can't scroll vertically in React mode

Question

I'm trying to display a modal in my React project. When the modal is shown, I set the body's overflow to hidden via useEffect (otherwise, it shows the scrollbar for the main content below the modal). It works perfectly to prevent the background content from scrolling, but the problem is that I can't scroll in the modal either. The main page code is as follows:

import React, { useState } from "react";
import { render } from "react-dom";
import MyModal from "./MyModal";
import "./index.css";

function App() {
  const [showModal, setShowModal] = useState(false);
  return (
    <div className="wrapper">
      <button
        onClick={() => {
          setShowModal((current) => !current);
        }}
      >
        {`${showModal ? "Hide Modal" : "Show Modal"}`}
      </button>
      {showModal && <MyModal {...{ showModal, setShowModal }} />}
      <p>
        Lorem Ipsum is simply dummy text of the printing and typesetting
        industry. Lorem Ipsum has been the industry's standard dummy text ever
        since the 1500s, when an unknown printer took a galley of type and
        scrambled it to make a type specimen book. It has survived not only five
        centuries, but also the leap into electronic typesetting, remaining
        essentially unchanged. It was popularised in the 1960s with the release
        of Letraset sheets containing Lorem Ipsum passages, and more recently
        with desktop publishing software like Aldus PageMaker including versions
        of Lorem Ipsum.
      </p>
      
    </div>
  );
}

render(<App />, document.getElementById("root"));

This is the code for the modal:

import { useEffect } from "react";
import "./modal.css";

const MyModal = ({ showModal, setShowModal }) => {
  useEffect(() => {
    document.body.style.overflowY = "hidden";
    return () => {
      document.body.style.overflowY = "auto";
    };
  }, []);
  return (
    <div className="modal-background">
      <button
        onClick={() => {
          setShowModal(false);
        }}
      >
        Close
      </button>
      <p className="heading">This is Modal</p>
      <p>
        Lorem Ipsum is simply dummy text of the printing and typesetting
        industry. Lorem Ipsum has been the industry's standard dummy text ever
        since the 1500s, when an unknown printer took a galley of type and
      </p>
    </div>
  );
};

export default MyModal;

This is a live example of codesandbox: https://codesandbox.io/s/lockingmodal-8mvn36?file=/index.js:1160-4493

Answer 1

Add these two lines to your class "modal-background"

height:50vh;
overflow:auto;