1145910 - Shadow DOM prevents :active pseudo class from matching on the shadow host

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Michael Henretty [:mikehenrty][:mhenretty]]

Attachment: [HTML page] test case

Attached test case. In the test case there is a blue box, which is the shadow host, that turns red on :active state. Inside that box is a shadow DOM box with a black border. Then inside that is a non-shadow span with the text "Text" inside of it.

Clicking on the blue box, or word "Text" triggers the :active pseudo selector. However, clicking withing the black border (ie. the shadow DOM box) and not on the "Text" will not trigger the :active class, and the host box stays blue. The shadow DOM must be preventing the :active state from propagating to normal web content.

Comment 1

[Michael Henretty [:mikehenrty][:mhenretty]]

William, any idea what's going on here?

Comment 2

[Michael Henretty [:mikehenrty][:mhenretty]]

Could be related to bug 1117535. I'm not sure.

Comment 3

[William Chen [:wchen]]

Attachment: Use flattened tree when updating ancestor state in event state manager.

The code to update the event state of content in the shadow DOM currently doesn't use the flattened tree when traversing ancestors so it stops at the shadow root.

Comment 4

[William Chen [:wchen]]

Attachment: Cross ShadowRoot boundary when updating ancestor state in event state manager.

Now with test.

Here is the relevant text in the selector spec:
http://dev.w3.org/csswg/selectors-4/#active-pseudo

Seems to be missing from the HTML spec:
https://html.spec.whatwg.org/multipage/scripting.html#selector-active

Comment 5

[William Chen [:wchen]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/380fb6484776

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/380fb6484776

Comment 7

[Michael Henretty [:mikehenrty][:mhenretty]]

Thanks William! Any chance we could request uplift to 37? This will help us improve the web components we are using for the lightsaber project, and I believe we want that working with b2g 2.2.

Comment 8

[Michael Henretty [:mikehenrty][:mhenretty]]

Nevermind, I just checked and we don't care about having lightsaber work on 2.2.

Comment 9

[Boris Zbarsky [:bzbarsky]]

Doesn't FindCommonAncestor need to be changed too?  Otherwise the optimization story for moving the mouse into/out of a component will kinda suck in terms of updating the :hover state, I'd think.