1564035 - Fixed content of fixed parent is not rendered when position changes

Status: RESOLVED DUPLICATE of bug 1200585

(Core :: Layout, defect)

Description

[odsasson]

Attachment: test.htm

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

The attached file contains a demo.

Actual results:

Child with position: fixed of parent with position: fixed is not rendered when the position of the parent changes.

Expected results:

Should have been rendered properly.

Comment 1

[Alice0775 White]

Regression window:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=6338a8988917&tochange=7e4c2abb9fc9
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=f56e2197d9cd&tochange=ec7c7be7c70d
https://hg.mozilla.org/integration/fx-team/pushloghtml?fromchange=b1338c3c89b2&tochange=2f324831c02d

Regressed by:
df6702c41ddd15b2071752ad27400a42df0a82a4 Ehsan Akhgari — Bug 157681 - Part 2: Optimize positioned frame offset changes by moving the frame as opposed to reflowing it in case we know that the size of the frame will not change; r=dbaron
59ff36c33e696f54469dbfcbff4b96446b4a8710 Ehsan Akhgari — Bug 157681 - Part 1: Add a test suite to make sure that dynamic changes to the position CSS properties work correctly; r=dbaron

Comment 2

[Emilio Cobos Álvarez [:emilio]]

This is bug 1200585, the nested child gets its hypothetical position from the parent.