Does the "shadow root" concept include UA shadow roots?

[mfreed7]

What is the issue with the HTML Standard?

This comes from this Chromium bug: https://crbug.com/505045915

The HTML spec says about :focus:

an element has the focus when:
...
its shadow root shadowRoot is not null and shadowRoot is the root of at least one element that has the focus.

The question is: does that apply to elements that have user agent shadow roots? E.g. <input>, <audio>, <video>, etc.?

Here's a test page, taken from the Chromium bug:

• https://jsbin.com/cagoqad/edit?html,output

There are some interesting differences between browsers. It seems to me that the correct behavior would be to honor UA shadow roots for :focus.

[annevk]

I don't think it was intended to include them, but now that we explicitly rely on user agent shadow roots here and there that obviously isn't tenable. We probably need to audit all callers. :-(

[mfreed7]

I don't think it was intended to include them, but now that we explicitly rely on user agent shadow roots here and there that obviously isn't tenable. We probably need to audit all callers. :-(

Ok. Also, it does seem like a natural developer expectation that :focus matches an element when something "inside" the element is focused, especially since that's true for custom elements.

[annevk]

Perhaps. I'm not intimately familiar with the focus decisions for the elements in question and your jsbin demo does not work (some intermediary error).

[mfreed7]

your jsbin demo does not work (some intermediary error).

Yeah, Jsbin's certificate unfortunately expired. I'm hoping they get it renewed soon.

[sb3nder]

Here's another link: https://codepen.io/sb3nder/pen/PwGvWBz