1532481 - Firefox does not expand certain list items so they do not vertically overlap, as other engines do.

Status: NEW

(Core :: Layout: Generated Content, Lists, and Counters, defect, P3)

Description

[Thomas Wisniewski [:twisniewski]]

Attachment: test.html

This test-case contains a simple list, where each item has a paragraph with a different line-height, but the list items themselves specify no line-height.

Blink, WebKit, and Edge will ensure the list items do not overlap, but Firefox will overlap them based on the line-heights stated by the paragraph elements.

This is causing Firefox to overlap text (unlike the other engines) on https://aspergersvic.org.au/Just-Diagnosed, as reported at https://webcompat.com/issues/26112

Note that if the list items themselves specify the line-height, rather than the paragraphs, then the other engines will also permit allow them to overlap.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Is this a regression? I'm a bit surprised by the behavior, and I don't think we used to do this.

Comment 2

[Thomas Wisniewski [:twisniewski]]

Good question. The testcase renders similarly for me in mozregression on Linux as far back as Firefox 5, so it would be a very old regression if it is one.

Comment 3

[Firefox Bug Husbandry Bot]

Migrating Webcompat whiteboard priorities to project flags. See bug 1547409.

Comment 4

[Firefox Bug Husbandry Bot]

See bug 1547409. Migrating whiteboard priority tags to program flags.

Comment 5

[Dennis Schubert [:denschub]]

This is still a valid issue as testcases still reproduce - however, we don't have any active non-testcase WebCompat breakage caused by this as the site reported here changed its layout and the new version does not show this issue. Unsetting the webcompat-priority flags per our rules.