Tabpanel pattern clarification question

Hi w3 folks,

In reading the specification for a tab panel<https://www.w3.org/WAI/ARIA/apg/patterns/tabpanel/> on the ARIA Authoring Practices Guide, I wasn’t sure how to interpret directions for vertically oriented tabs:

When a tab list has its aria-orientation set to vertical:

  1.  Down Arrow performs as Right Arrow is described above.
  2.  Up Arrow performs as Left Arrow is described above.

For a vertically oriented tab list, should the Right Arrow and Left Arrow keys be inert? Or should they still move to next/previous tab?

Thanks for any feedback,

Casey Hickey