1376040 - abspos flex item seems to be incorrectly influencing other flex items, in modified "customize" view

Status: RESOLVED INCOMPLETE

(Core :: Layout, defect, P3)

Description

[Daniel Holbert [:dholbert]]

STR:
 1. Update your mozilla-central to a cset from ~today, like this one for example:
   https://hg.mozilla.org/mozilla-central/rev/75be6742abb9

 2. Apply https://bugzilla.mozilla.org/attachment.cgi?id=8880613
 3. Open Hamburger Menu and click "Customize"
 4. Drag some items from the left into the right. Try hovering & un-hovering the right half.

ACTUAL RESULTS:
When you don't hover the right half, the content gets pushed to the bottom. It looks like this is from an abspos pseudo-element with "height:100%" is absorbing all of the free space, as noted in bug 1373968 comment 6.

EXPECTED RESULTS:
The abspos pseudo-element shouldn't influence the layout of its sibling flex items.

Comment 1

[Daniel Holbert [:dholbert]]

(In reply to Daniel Holbert [:dholbert] from comment #0)

STR:

1. Update your mozilla-central to a cset from ~today, like this one for
   example:
   https://hg.mozilla.org/mozilla-central/rev/75be6742abb9

2. Apply https://bugzilla.mozilla.org/attachment.cgi?id=8880613

Patch no longer applies. Resolving as INCOMPLETE since this isn't testable at this point.

This may have been some sort of XUL-layout-vs-html-layout interaction, perhaps? Or some layout bug that we've since fixed. Hard to know at this point. If the underlying issue here is still reproducible, we can track it in a new bug if/when we come across content that triggers similar trouble.