946920 - Moving a child element outside of a parent element while moving the parent element, both using transform: translate(), will cause the child element to disappear

Status: VERIFIED FIXED

(Core :: Web Painting, defect, P3)

Description

[Patrik Elfström]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0 (Beta/Release)
Build ID: 20131112160018

Steps to reproduce:

Moving a child element for example -10px using transform: translate() and at the same time moving the parent element 10px also using transform: translate().

Here is an example: http://jsbin.com/IsIVoyox/1/edit
(hover the red elements)

Bug appears in Firefox 25.0.1 and Firefox 28.0a1.
Works as it should in Chrome, Safari and Internet Explorer 10.



Actual results:

When the child element goes outside of the parent element it will disappear.
This however does seem to depend on the size of the child element and the distance it's moved.


Expected results:

The child element should still be visible when outside the parent element.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Confirmed on Mac too.

Comment 2

[Timothy Nikkel (:tnikkel)]

Works fine with 2013-02-01 nightly. So I think the next step is to get a regression range here.

Comment 3

[Patrik Elfström]

Works in Firefox 21.0b7 but not in 22.0
Tested on win7

Comment 4

[Timothy Nikkel (:tnikkel)]

Great. If we could get that bisected down to a single day of changesets that would be amazing. mozregression can help do it quicker, instructions here http://mozilla.github.io/mozregression/

Comment 5

[Patrik Elfström]

Last good revision: eccf45749400 (2013-03-11)
First bad revision: 7433bc4545c9 (2013-03-12)

Comment 6

[Timothy Nikkel (:tnikkel)]

Thank you!

That gives these changesets
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=eccf45749400&tochange=7433bc4545c9

Comment 7

[Timothy Nikkel (:tnikkel)]

Hmm, the only changeset in there that looks like it could have affected this is

http://hg.mozilla.org/mozilla-central/rev/9a9689e414e4

form bug 849263.

Comment 8

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

...which was making a previous change that Matt made actually do what it was supposed to do.

Comment 9

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

(Though I'm actually a bit skeptical of that being the cause, since it really should have changed perf rather than behavior.)

Comment 10

[Boris Zbarsky [:bzbarsky]]

There were actually two regression ranges, afaict.

First one is indeed http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=eccf45749400&tochange=7433bc4545c9 where the behavior changed to the the blue square disappearing while the red one is moving but reappearing once the red one stops.

Second one, to the current behavior: http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=97cfc16ba5dc&tochange=c232bec6974d

Comment 11

[Boris Zbarsky [:bzbarsky]]

Local bisect says that either bug 849263 or the landing/backout of bug 804944 that happened at the same time triggered the first regression.  My money is on the former.

Comment 12

[Timothy Nikkel (:tnikkel)]

Fixed by bug 944291.

Comment 13

[Bogdan Maris, Desktop QA]

Verified as fixed on latest Aurora 28.0a2 as well using Ubuntu 12.04 x32 and Windown 8.1 x32