AX: Scrolling containers inoperable with keyboard

• Component: Accessibility
• Status: NEW ---

[Adrian Roselli]

Abstract:
For containers that allow scrolling, a keyboard-only user cannot scroll the container.

To reproduce the problem:
1. Using Safari with FKA, go to https://cdpn.io/aardrian/debug/bGLrYBo
2. Size the window so the table is clipped and scrollbars appear below it.
2. Using _only_ the keyboard, attempt to scroll the table left or right.

What is the expected behavior?
I should be able to scroll the table so I can see all the columns.

What went wrong?
Unless the table has an interactive control within that can take focus, there is no way for a user to scroll a container using just the keyboard.

Does this work in other browsers?
Yes. Firefox has had support since version 4. Chrome added support this week in version 127.

More detail:
Mouse Keys is insufficient since it mimics a mouse interaction.

Today, authors must make the container focusable (`tabindex="0"`) to meet WCAG 2.2 SC 2.1.1 Keyboard, and then they must add an appropriate ARIA role and accName to satisfy SC 4.1.2 Name, role, value. Once WebKit treats scrolling containers as focusable, authors will no longer need to create verbose ARIA-driven patterns.

[Radar WebKit Bug Importer]

<rdar://problem/132760015>