Preview menu: arrows navigation doesn't work

[afercia]

Describe the bug
The WordPress 5.5 block editor will ship with a new "Preview" menu with options for desktop, tablet, mobile, and traditional preview in a new browser tab. Since it's an ARIA menu and looks like other menus where arrows navigation works, I'd expect arrows navigation to work on this menu as well. It doesn't.

To reproduce

• edit a post
• use the keyboard
• tab to the Preview menu button
• press Enter to open the menu
• the menu opens and focus is moved to the first menu item: so far so good
• use the Down and Up arrow keys to try to navigate through the menu items
• nothing happens

Additionally:

• open your browser's dev tools or shrink the browser's window height so that the page has some scrolling
• observe that while using the arrow keys on the menu items, the page (see the admin menu) scrolls, which means the default action is not prevented

Animated GIF:

Expected behavior
Arrows navigation on the Preview menu items to work and the default action to be prevented.

Editor version (please complete the following information):

• WordPress version: 5.5 Beta 2
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? Tested both
• If the Gutenberg plugin is installed, which version is it? 8.7.0 latest master

Noting that, technically, this is not a regression but it's a new feature introduced in WordPress that doesn't meet the expected accessibility best practices.

[ntsekouras]

Thanks for reporting this @afercia!