2016387 - ::selection is not inherited across trees

Status: NEW

(Core :: Layout, defect, P3)

Description

[Keith Cirkel [:keithamus]]

Attachment: Test Case

In a page with a global ::selection style, shadowroots will not inherit background/foreground colors of the selection.

This is inconsistent with other browsers such as Chrome.

STR:

1. Open the attached test case.
2. Press Ctrl+A or otherwise select all the text.
3. Observe the selection colors

Expected:

• All selected text uses a hotpink backround with teal text.

Actual:

• The text in the "light DOM" uses hotpink/teal, but the shadowdom nodes are selected with the default selection colors.

Chrome is as expected, Firefox 147-nightly (likely earlier also) is not.

Comment 1

[silverwind]

Both Chrome and Safari allow propagation of ::selection styles into the Shadow DOM. I think Firefox should allow it too because a selection is generally not considered to be a part of an element, but part of the browser's UI and therefor needs no encapsulation.