Material-ui: MenuItem doesn't respect focusVisibleClassName

[ianschmitz]

Related to #10976.

The changes in #10976 work awesome for the Switch, however it looks like the MenuItem's focusVisibleClassName prop doesn't work as expected. Passing a focusVisibleClassName to the item works great from a typing perspective, but they don't seem to be applied to the ListItem correctly.

Example: https://codesandbox.io/s/5638ox58n

[oliviertassinari]

@ianschmitz Correct, we need to merge the classnames in
https://github.com/mui-org/material-ui/blob/e99f23e85f9f0241a08165b435cd4d51f696ac12/packages/material-ui/src/ListItem/ListItem.js#L108

[ashwani-pandey]

Hi @oliviertassinari, can i take up this issue to solve, as i am a beginner and looking forward to contribute to material-ui :)

[oliviertassinari]

We are happy to hear you want to contribute to Material-UI but @rdemirov is already working on this issue. Don't worry, there is a lot that can be improved.