Use a divider prop (which adds a bottom border) instead of a Divider component...

Use a divider prop (which adds a bottom border) instead of a Divider component (which gets keyboard focus) in Menus

__tests__/src/components/WindowTopMenu.test.js

@@ -2,7 +2,6 @@ import React from 'react';
 import { shallow } from 'enzyme';
 import ListItem from '@material-ui/core/ListItem';
 import Menu from '@material-ui/core/Menu';
-import Divider from '@material-ui/core/Divider';
 import WindowThumbnailSettings from '../../../src/containers/WindowThumbnailSettings';
 import WindowViewSettings from '../../../src/containers/WindowViewSettings';
 import { WindowTopMenu } from '../../../src/components/WindowTopMenu';
@@ -27,7 +26,6 @@ describe('WindowTopMenu', () => {
     expect(wrapper.find(ListItem).length).toBe(2);
     expect(wrapper.find(WindowThumbnailSettings).length).toBe(1);
     expect(wrapper.find(WindowViewSettings).length).toBe(1);
-    expect(wrapper.find(Divider).length).toBe(2);
   });
 
   it('passes windowId to <WindowThumbnailSettings/>', () => {

src/components/WindowTopMenu.js

 import React, { Component } from 'react';
 import ListItem from '@material-ui/core/ListItem';
 import Menu from '@material-ui/core/Menu';
-import Divider from '@material-ui/core/Divider';
 import PropTypes from 'prop-types';
 import WindowThumbnailSettings from '../containers/WindowThumbnailSettings';
 import WindowViewSettings from '../containers/WindowViewSettings';
@@ -38,14 +37,12 @@ export class WindowTopMenu extends Component {
           open={Boolean(anchorEl)}
           onClose={handleClose}
         >
-          <ListItem>
+          <ListItem divider>
             <WindowViewSettings windowId={windowId} />
           </ListItem>
-          <Divider />
-          <ListItem>
+          <ListItem divider>
             <WindowThumbnailSettings windowId={windowId} />
           </ListItem>
-          <Divider />
         </Menu>
       </>
     );

src/components/WorkspaceMenu.js

 import React, { Component } from 'react';
 import Menu from '@material-ui/core/Menu';
-import Divider from '@material-ui/core/Divider';
 import ListItemIcon from '@material-ui/core/ListItemIcon';
 import MenuItem from '@material-ui/core/MenuItem';
 import Typography from '@material-ui/core/Typography';
@@ -130,11 +129,10 @@ export class WorkspaceMenu extends Component {
             <Typography varient="inherit">{t('selectWorkspaceMenu')}</Typography>
           </MenuItem>
 
-          <NestedMenu label={t('language')}>
+          <NestedMenu label={t('language')} divider>
             <LanguageSettings afterSelect={handleClose} />
           </NestedMenu>
 
-          <Divider />
           <MenuItem
             aria-haspopup="true"
             onClick={(e) => { this.handleMenuItemClick('settings', e); handleClose(e); }}