1729627 - Add-on popups not using screen scaling on second monitor

Status: RESOLVED FIXED

(Core :: Widget: Win32, defect)

Description

[alvinhochun]

Attachment: Screenshot showing defect on secondary monitor

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0

Steps to reproduce:

1. Have two monitors, primary monitor set to 150% display scaling and secondary monitor set to 100% display scaling
2. Install add-on (e.g. uBlock Origin)
3. Open add-on popup with Firefox window on secondary monitor

Actual results:

Add-on popup uses scaling of primary monitor instead of secondary monitor.

Expected results:

Add-on popup shall use scaling of secondary monitor.

Comment 1

[alvinhochun]

Attachment: Screenshot showing normal behaviour on primary monitor

Comment 2

[alvinhochun]

Attachment: Screenshot showing normal behaviour on Firefox 92

Comment 3

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

The Bugbug bot thinks this bug should belong to the 'WebExtensions::Untriaged' component, and is moving the bug to that component. Please revert this change in case you think the bot is wrong.

Comment 4

[Estanislao Larriera]

Hi alvinhochun,

Thanks for your report. I was able to reproduce your issue on Nightly 94.0a1, Beta 93.0b3 and the current Release build 92.0, so I´ll mark this as "New" for visibility and add a proper Component to it. I will see if there's a regression for this asap.

Also there's this bug that looks similar to the issue you are reporting, please take a look: https://bugzilla.mozilla.org/show_bug.cgi?id=1472691

Thanks!

Estanislao

Comment 5

[alvinhochun]

Hi, I am dumbfound that you are able to reproduce this on 92. To me this is a regression in 93 beta. Firefox 92 and older versions had been working completely fine in regard to this issue.

The referenced bug 1472691 may seem similar in first sight, but there are differences:

1. The issue I am getting had not shown up on Firefox 92 or previous versions (going all the way back to Firefox 70 or earlier).
2. My two monitors are set up side-by-side, not vertically as in the other bug report.
3. In the other bug report, you can see that the content of the pop-ups are shown in the correct screen scaling (the Firefox UI and the content of the pop-ups are scaled by the same ratio in both screenshots), while in the screenshot I posted, the content of the pop-up is noticeably scaled as 150% while the rest of the Firefox UI is scaled at 100%.

Comment 6

[alvinhochun]

Okay, I bisected with mozregression and found https://phabricator.services.mozilla.com/D122027 for fixing bug 1722085 to be the change that caused the bug, which is very likely to be the cause given what it changed.

Comment 7

[Masatoshi Kimura [:emk]]

Oh, bug 1264196 regressed after all?

Comment 8

[Masatoshi Kimura [:emk]]

We should call ::GetAncestor even if GetDpiForWindow is available:
https://searchfox.org/mozilla-central/rev/1761c710b035d7dc8892dfa8e56589b4e095221f/widget/windows/WinUtils.cpp#685

Comment 9

[Masatoshi Kimura [:emk]]

Attachment: Bug 1729627 - Call ::GetAncestor even if GetDpiForWindow is available r?handyman

Comment 10

[Darren Henderson]

(In reply to alvinhochun from comment #6)

Okay, I bisected with mozregression and found https://phabricator.services.mozilla.com/D122027 for fixing bug 1722085 to be the change that caused the bug, which is very likely to be the cause given what it changed.

I found the same. I don't see the behavior in 92.

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/79fc53d43ea6
Call ::GetAncestor even if GetDpiForWindow is available r=handyman

Comment 12

[alvinhochun]

I verified with autoland builds that commit 79fc53d43ea6f3d332431c3cc56b0637815fc7c9 fixed the bug on my system.

Comment 13

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/79fc53d43ea6

Comment 14

[Masatoshi Kimura [:emk]]

Comment on attachment 9240690 [details]
Bug 1729627 - Call ::GetAncestor even if GetDpiForWindow is available r?handyman

Beta/Release Uplift Approval Request

• User impact if declined: Add-on popups will not be shown correctly on some multi-monitor configurations.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): This patch just partially restore a necessary call we did it before bug 1722085.
• String changes made/needed: none

Comment 15

[Pascal Chevrel:pascalc (PTO until April 26)]

Comment on attachment 9240690 [details]
Bug 1729627 - Call ::GetAncestor even if GetDpiForWindow is available r?handyman

Low risk fix for a 93 regression. Approved for 93 beta 6, thanks.

Comment 16

[Pascal Chevrel:pascalc (PTO until April 26)]

https://hg.mozilla.org/releases/mozilla-beta/rev/b1cb0cd7c3aa