629352 - OL lists apply line-height inconsistently

Status: NEW

(Core :: Layout: Block and Inline, defect)

Description

[Scott Gould]

User-Agent:       Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0b10) Gecko/20100101 Firefox/4.0b10
Build Identifier: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:2.0b10) Gecko/20100101 Firefox/4.0b10

For OL lists, line-heights below the default are not applied.

Reproducible: Always

Steps to Reproduce:
1. Set a line-height on an OL list at a value below 'normal'.

Actual Results:  
The line-height of the list does not drop below the value of 'normal'.

Expected Results:  
The line-height should be honored, even if below 'normal'.

Tried explicitly setting the line-height on 'li' as well as using '!important' on line-height directives for both 'ol' and 'li'; neither had any effect. No apparent workaround that I could find.

Comment 1

[Scott Gould]

Attachment: Test case HTML file.

Comment 2

[Scott Gould]

Attachment: Example of expected results (from Safari)

Comment 3

[Scott Gould]

Attachment: Example of issue (from Firefox 4.0b10)

Comment 4

[(mostly gone) XtC4UaLL [:xtc4uall]]

Seeing this with Mozilla/5.0 (Windows NT 5.1; rv:2.0b11pre) Gecko/20110127 Firefox/4.0b11pre ID:20110127030333

Comment 5

[Boris Zbarsky [:bzbarsky]]

Per CSS2.1, this is invalid, as far as I can tell.  If you make your window narrow enough, you will see that the small line-height setting is affecting all the lines of the list item except the first line.  And the reason it doesn't affect the first line is because these are outside list markers, and the spec at http://www.w3.org/TR/CSS21/generate.html#propdef-list-style-position says:

  The size or contents of the marker box may affect the height of the principal
  block box and/or the height of its first line box

In particular, we make the first line's box tall enough for the marker.  This happens to be taller than the strut that line-height inserts, so the line ends up taller than the specified line-height.

Per the CSS3 Lists draft, I'm not sure.  That specifies that the marker box is an inline-block.  Presumably it would inherit line-height from the block, right?  In that case its height for vertical-alignment purposes should be equal to the line height, I'd think.

Comment 6

[Ron Patterson]

This bug, as accurately reported by Scott Gould, 2011.01.27, is still alive in Firefox major version 8.0.  It seems to be a carryover from the incorrectly written standard in CSS2.1.

Comment 7

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

Seems like what css3-lists suggests is the right thing here.