`@mui/styles` is not compatible with React.StrictMode or React 18.

[h4rkl]

Checklist

• [x] This is not covered in the repository examples.
• [x] I am using the package latest version.
• [x] This is a bug report or an enhancement proposal.

Background

Directly related to issue TypeError: theme.spacing is not a function

Description

Anyone getting TypeError: theme.spacing is not a function looks like quite a major bug as import { ThemeProvider } from '@mui/styles' isn't compatible with React 18 and import { ThemeProvider } from '@mui/material/styles' is the documented correct way to implement theming on mui which includes a tonne of dependancies in the docs like dark mode etc.

To read about the implications of using legacy import for @mui/styles go here.

[h4rkl]

Duplicate of #284 and #310

[pisze-programy]

https://github.com/niuware/mui-rte/issues/285#issuecomment-975526864