Select and Menu components freeze inside custom HTMLElement

[PatriciaRomaniuc]

Steps to reproduce

minimal code example:

import React, { createRef } from 'react';
import { createRoot } from 'react-dom/client';
import Select from '@mui/material/Select';
import MenuItem from '@mui/material/MenuItem';

class MyCustomElement extends HTMLElement {
  connectedCallback() {
    this._root = createRoot(this);
    this._root.render(<MySelect />);
  }
  disconnectedCallback() {
    this._root.unmount();
  }
}

const MySelect = () => {
  const [value, setValue] = React.useState('');
  const ref = createRef();

  return (
    <Select
      value={value}
      onChange={(e) => setValue(e.target.value)}
      inputRef={ref}
    >
      <MenuItem value="one">One</MenuItem>
      <MenuItem value="two">Two</MenuItem>
    </Select>
  );
};

customElements.define('my-custom-element', MyCustomElement);

Current behavior

When using MUI Select inside a custom HTMLElement with React createRoot(this) opening the Select causes the page to freeze and throws:

useTimeout.js:25 Uncaught TypeError: fn is not a function

This appears to be related to MUI Select relying on Popover + Grow + internal refs, which break when the component is rendered directly inside a custom element.

using transitionDuration={0} into MenuProps fixes the issue, but it's not ideal

Expected behavior

The Select dropdown should open without freezing, similar to how Popover works in a stable container.

Context

No response

Your environment

npx @mui/envinfo

System:
OS: macOS 14.6.1
Binaries:
Node: 20.8.0 - /Users/patriciaromaniuc/.nvm/versions/node/v20.8.0/bin/node
npm: 10.1.0 - /Users/patriciaromaniuc/.nvm/versions/node/v20.8.0/bin/npm
pnpm: 8.9.0 - /Users/patriciaromaniuc/.nvm/versions/node/v20.8.0/bin/pnpm
Browsers:
Chrome: 142.0.7444.60
Edge: Not Found
Firefox: 137.0
Safari: 18.3.1
npmPackages:
@emotion/react: 11.14.0
@emotion/styled: 11.14.1
@mui/core-downloads-tracker: 7.3.4
@mui/icons-material: 7.3.4
@mui/material: 7.3.4
@mui/types: 7.4.7
@types/react: 19.2.2
react: 18.2.0 => 18.2.0
react-dom: 18.2.0 => 18.2.0
styled-components: 5.3.11
typescript: 3.9.10

Search keywords: useTimeout, Select, Menu, Grow

[ZeeshanTamboli]

Please provide a live reproduction in the form of Stackblitz or CodeSandbox. Here's a good starting template: https://stackblitz.com/github/mui/material-ui/tree/master/examples/material-ui-vite-ts?file=src%2FApp.tsx

[rithik56]

@ZeeshanTamboli can I work on this issue ?

[PatriciaRomaniuc]

I tried to make an example here https://stackblitz.com/edit/github-gshwyya8?file=src%2FApp.jsx but something is off with the custom elements declaration in this type of environment. @rithik56 if you want to help, that would be great.

[PatriciaRomaniuc]

I did add a workaround to this issue and but it's not great since the focus is also an issue and I am basically trying to make it look like MUI transition without it

import React from 'react';
import { Select } from '@mui/material';

export const WebComponentSafeTransition = React.forwardRef(({ children, in: inProp }, ref) => {
    const [mounted, setMounted] = React.useState(false);

    React.useEffect(() => {
        if (inProp) {
            // Use RAF to ensure the element is mounted before applying the visible class
            requestAnimationFrame(() => {
                requestAnimationFrame(() => {
                    setMounted(true);
                });
            });
        } else {
            setMounted(false);
        }
    }, [inProp]);

    if (!inProp && !mounted) {
        return null;
    }

    const style = {
        opacity: mounted ? 1 : 0,
        transform: mounted ? 'scaleY(1) translateY(0)' : 'scaleY(0.3) translateY(-10px)',
        transition: 'opacity 350ms cubic-bezier(0.4, 0, 0.2, 1), transform 350ms cubic-bezier(0.2, 1, 0.2, 1)',
        transformOrigin: 'top center',
    };

    return (
        <div ref={ref} style={style}>
            {children}
        </div>
    );
});

/**
 * Web Component-safe Select wrapper
 *
 * Fixes MUI Select crash when used inside custom HTMLElements with createRoot(this)
 *
 * Required fixes:
 * - disablePortal: true - Keeps menu in Web Component's React tree
 * - TransitionComponent: Custom - Bypasses Grow transition's useTimeout
 *
 * Features:
 * - Dropdown-style animation (scaleY + translateY)
 * - Menu may be clipped by parent overflow: hidden
 * - Menu won't break out of scrolling containers
 *
 * @param {object} props - All standard MUI Select props
 */
export const WebComponentSafeSelect = ({ MenuProps = {}, ...props }) => {
    const ref = React.useRef(null);

    // implement onClose and onOpen to manage focused class based on workaround for MUI bug found in stackoverflow
    const onClose = () => {
        ref.current?.previousSibling?.classList.remove('Mui-focused');
        ref.current?.classList.remove('Mui-focused');

        if (props.onClose) {
            props.onClose();
        }
    };

    const onOpen = () => {
        ref.current?.previousSibling?.classList.add('Mui-focused');
        ref.current?.classList.add('Mui-focused');

        if (props.onOpen) {
            props.onOpen();
        }
    };

    return (
        <Select
            {...props}
            ref={ref}
            autoFocus={false}
            onOpen={onOpen}
            onClose={onClose}
            MenuProps={{
                ...MenuProps,
                disablePortal: true,
                TransitionComponent: WebComponentSafeTransition,
                disableAutoFocusItem: true,
                PaperProps: {
                    style: {
                        maxHeight: '300px',
                        marginTop: '4px',
                        ...MenuProps.PaperProps?.style,
                    },
                    ...MenuProps.PaperProps,
                },
            }}
        />
    );
};

export default WebComponentSafeSelect;

[ZeeshanTamboli]

We can't help without a clear reproduction. You can also provide a minimal example in the form of a GitHub repository with steps to reproduce the issue.