Screen reader issues with admin navigation sidebar

[Thibaud Colas]

There are three issues with the admin’s toggle-able sidebar nav for screen reader users:

• Its toggle button doesn’t set aria-expanded to indicate its state. This is important so people can tell whether the current state is "opened" or "closed".
• The sidebar is wrapped in a <nav> landmark (good!) but that landmark should ideally have a label set with aria-label="{% translate 'Sidebar' %}" so users can more easily decide whether this is the part of the UI they want to go to.
• The sidebar shouldn’t be navigable when closed (to replicate the experience of sighted users). This is because we’re preventing navigation by setting tabindex="-1" on the sidebar interactive elements. Instead, we should set the whole region to display: none or visibility: hidden when closed.

[Gloib]

​patch created here

[Mariusz Felisiak <felisiak.mariusz@…>]

In c4aac2ac:

Fixed #34042 -- Improved accessibility of admin's navigation sidebar.