1553007 - Addons that draw to the sidebar cause page elements to render at the wrong depth.

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect, P2)

Description

[Evan Banyash]

Attachment: The bug in action.

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0

Steps to reproduce:

1. Install any addon that uses the sidebar, e.g. Tab Center Redux or Tree Style Tab.
2. Look at some page that uses a fixed positioned overlay element that floats over text and images. The Firefox homepage is an example. Recoil in horror.
3. Disable the addon, hide the sidebar or navigate the sidebar to a built-in screen, and notice the page rendering return to normal with everything at the correct depth.

Actual results:

Page text and images that clearly are meant to be below some overlay element on top of them actually draw on top of it instead! This even affects the Firefox homepage (see attached).

This only seems to happen on Nightly, stable apparently unaffected.

Expected results:

The text and images should be drawn below fixed positioned overlay elements with higher z-indexes.

Comment 1

[Evan Banyash]

Attachment: Normal behavior.

Comment 2

[Raluca Popovici, Desktop QA]

Attachment: 2019-05-27_10h52_07.png

Comment 3

[Raluca Popovici, Desktop QA]

Hi,

I was able to reproduce this bug only on Nightly 69.0a1. I cannot reproduce it in Firefox Release 67.0 and Firefox Beta 68.0b4.

Steps to reproduce:

1. Install Tree Style Tab addon that uses the sidebar.
2. Look at some page that uses a fixed positioned overlay element that floats over text and images. The Firefox homepage is an example. Scroll down the page

Actual results:

Page text and images that clearly are meant to be below some overlay element on top of them actually draw on top of it instead! This even affects the Firefox homepage (see attached).

Expected results:

The text and images should be drawn below fixed positioned overlay elements with higher z-indexes.

I also performed a mozregression in order to get a Regression range and here are the results.

First bad build https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=2ccc6648064315964dd23039ad28ebf7d9f82999&tochange=7e40e33da3da2640e965a153254594a234231f76

Last known Good build https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=45e3c6135d0759e37a270e4ff0d8cf1d0ec03f21&tochange=7e40e33da3da2640e965a153254594a234231f76

Thanks for your report.

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

The priority flag is not set for this bug.
:dholbert, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 5

[Emilio Cobos Álvarez (:emilio)]

This looks more like graphics / web painting-land. For such a recent regression it looks like we ought to be able to find a narrower regression range....

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Seems like a recent regression that affects popular add-ons.

Comment 7

[Jessie [:jbonisteel] pls NI]

Matt, any thoughts on what might have caused this?

Comment 8

[Matt Woodrow (:mattwoodrow)]

This seems like a retained display list regression, but I don't see anything relevant within the regression range.

I also haven't been able to reproduce it yet on OSX, could be platform specific.

Adding regressionwindow-wanted to see if we can get a narrower regression range.

Comment 9

[evgeny.she+git]

Attachment: shrunk overlay

Comment 10

[evgeny.she+git]

Maybe related: Scaling of fixed elements is weird for a few days already (Nightly, currently @69.0a1 (2019-06-19) (64-bit) Linux). Not related to extensions, I guess (I don't have any sidebars) but if you scale page down they are not scaled properly. See screenshot: it's a basic modal window with fixed full-screen semi-transparent div, scaled to 80%. Normally it covers whole screen no matter chosen scale

Comment 11

[Alice0775 White]

(In reply to evgeny.she+git from comment #9)

Created attachment 9072972 [details]
shrunk overlay

This is Bug 1559518

Comment 12

[Evan Banyash]

(In reply to Matt Woodrow (:mattwoodrow) from comment #8)

This seems like a retained display list regression, but I don't see anything relevant within the regression range.

I also haven't been able to reproduce it yet on OSX, could be platform specific.

Adding regressionwindow-wanted to see if we can get a narrower regression range.

You're right, it doesn't happen at all on OSX, just Windows from my testing. Haven't tried on Linux.

Comment 13

[Liz Henry (:lizzard) (relman/hg->git project)]

Matt, is this something you can work on or help find an owner for it? We'd like to get a fix for this into 69 if possible.

Comment 14

[Matt Woodrow (:mattwoodrow)]

Miko, do you have time to look at this? Even just reproducing it and getting a regression range would be useful.

Comment 15

[Miko Mynttinen]

(In reply to Matt Woodrow (:mattwoodrow) from comment #14)

Miko, do you have time to look at this? Even just reproducing it and getting a regression range would be useful.

I tried to reproduce this on Windows 10 (1920x1080 resolution) and macOS (retina and 1920x1200 resolution), with various builds between 2019-05-01 and 2019-07-12. I was not able to reproduce this with or without WebRender. I tried with Tree Style Tabs and Tab Center Redux -addons.

I have seen this behavior intermittently on my Mac before though.

Comment 16

[Miko Mynttinen]

Raluca, can you still reproduce this? If so, do you have steps to reproduce with a new profile?

Comment 17

[Rares Doghi, Desktop QA]

Hi Miko, me and Raluca both managed to reproduce this issue in an older build by simply installing the Add-on Tree Style Tab and setting the region in about:config to US so we can see the pocket recommendations after which we just opened a new tab and scrolled through the page.

I have retested this issue now in Firefox 68, Beta 69.0b5 and our latest Nightly build 70.0a1 (2019-07-18) and the issue no longer occurs. Please let me know if you want us to mark this issue as Resolved Works for Me.

Comment 18

[Miko Mynttinen]

(In reply to Rares Doghi from comment #17)

Hi Miko, me and Raluca both managed to reproduce this issue in an older build by simply installing the Add-on Tree Style Tab and setting the region in about:config to US so we can see the pocket recommendations after which we just opened a new tab and scrolled through the page.

I have retested this issue now in Firefox 68, Beta 69.0b5 and our latest Nightly build 70.0a1 (2019-07-18) and the issue no longer occurs. Please let me know if you want us to mark this issue as Resolved Works for Me.

Thank you for the clarification and retesting this. It sounds likely that this bug has been fixed at some point, I'll mark it as WFM.