"Button-bar" mode in MenuBar

[rolfsmeds]

Description

An interaction mode for the MenuBar that makes top-level menu items (menu bar buttons) traversable by tab instead of arrow keys (i.e. disabling roving tabindex)

Use cases

As a user I expect to traverse between buttons in a MenuBar with tab So that I can traverse them the same way as normal buttons

Acceptance criteria

• [x] API for enabling the "tab navigation" mode, e.g.
  • [ ] WC / React: tabNavigation property
  • [ ] Flow: setTabNavigation(boolean)
• [x] Disables roving tabindex, setting a static tabindex="0" on all vaadin-menu-bar-buttons (except disabled ones)
• [x] Replaces role="menubar" with role="group" on vaadin-menu-bar
• [x] Replaces role="menuitem" with role="button" on vaadin-menu-bar-button

General criteria

• [ ] APIs reviewed

• [ ] Design

• [ ] Performance

• [ ] UX/DX tests in Alpha

• [ ] Documentation:

• [ ] How to test?

• [ ] Limitations:

Security

• [ ] Security implications have been taken into account (elaborate or link to product security requirement specification if there are implications)