bug: Arrow Keys do not seem to work with Popover

[RobertWeaver]

Bug Report

Ionic version:
[ ] 4.x
[ ] 5.x
[x] 6.x

Current behavior:
When using the keyboard to interact with the Popover the arrow keys do not move up and down the list items. Once the trigger button has focus I can open the menu with the space or enter key and then tab between the items. But up and down arrow does not work.

Expected behavior:
The documentation confirms the arrow keys should work for keyboard navigation between items.

https://beta.ionicframework.com/docs/api/popover#keyboard-navigation

Angular Material opens a select style dropdown with the first item already focused saving a key stroke. It would be good to have such a feature for desktop users.

https://material.angular.io/components/select/overview#select-form

Also the regular Angular Material Menu dropdown can navigate down to nested menus using only arrow keys.

https://material.angular.io/components/menu/examples#menu-icons

Steps to reproduce:
Click or set focus to a button that can open a Popover then use the tab key to focus to first item then try to use arrow keys to move up and down between items.

Related code:
CodeSandBox Demo using Ionic Custom Elements
https://codesandbox.io/s/thirsty-brook-b9lhr?file=/src/index.js

Ionic info:
Ionic 6.0.0-dev.202106232232.ceabba1

[willmartian]

Thanks for the issue! This has been resolved and a fix will be available in the next beta release of Framework v6.

[ionitron-bot]

Thanks for the issue! This issue is being locked to prevent comments that are not relevant to the original issue. If this is still an issue with the latest version of Ionic, please create a new issue and ensure the template is fully filled out.