Discussing how to focus navigate absolute position elements that are focusable in CSS reading-flow

[dizhang168]

What is the issue with the HTML Standard?

As brought up by @emilio during the WHATNOT meeting, elements that have CSS position: absolute do not participate in the grid/flex layout. Its focus navigation order is hence unclear, similar to the display: contents case (#10533).

Example:
https://codepen.io/mfreed7/pen/poXeVbv

The proposal for reading-flow focus navigation should handle this case.

[dizhang168]

For elements that are not included in the flex/grid layout such as position: absolute, we propose visiting them at the end of the reading flow, in DOM order.

[annevk]

Marking this agenda+ as there's a PR in progress (#10613) and this seems relevant to resolve beforehand.

[dizhang168]

Current proposed resolution is to visit all out of flow children with no reading flow order information (such as elements with CSS position: absolute) after the valid rendering-defined sibling reading flow, in DOM tree order.

Since the 'reading-flow property is meant for navigating flex/grid/etc items in visual order, cases like "position: absolute" are rare. We haven't received any oppositions to move forward with the above resolution.

[chrishtr]

Closing this issue since there is nothing left to track here specifically.