1435529 - UI elements (some menus, popups) are wrong size on second monitor

Status: RESOLVED WORKSFORME

(Core :: Widget: Win32, defect, P3)

Description

[Sujay Parekh]

Attachment: Extension popup too large

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0
Build ID: 20180103231032

Steps to reproduce:

OS: Windows 10
Setup: Dual monitor setup - Laptop with 3200x1800 screen + LCD with 1920x1200
Firefox: v57.0.4

Open Firefox windows on both screens. The main content shows "proper" sizing on both screens. However, some UI elements are incorrectly sized on my second screen, like:
1. toolbar menus from extensions (I tried LastPass, Ghostery, Xmarks)
2. input popups (eg, from "about:config" screen)
3. "about firefox" popup opened from menu bar

In case it matters, the Firefox was started when laptop was not connected to any monitors.

Also in case it matters, the "layout.css.devPixelsPerPx" setting is at its default value of "-1.0".


Actual results:

The UI elements on the LCD screen are too large. Some of the menus can't even be seen fully - it seems their container window is sized for one font size but the contents are sized differently.

Note that the rest of Firefox UI elements have proper size - size of text in pages loaded, Bookmarks Toolbar items and menus, popup menu or sidebar from the "Downloads" and "Bookmarks" buttons.


Expected results:

The contents of the menus and popup should match the scaling of the rest of the Firefox UI.

Note that if I change the "layout.css.devPixelsPerPx" setting, the above items do resize, but then the rest of the elements are incorrectly sized.

So it seems the layout.css.devPixelsPerPx setting does affect these UI elements, but they just seem to use a wrong value when created/rendered.

Comment 1

[Sujay Parekh]

Attachment: Input popup too large

Comment 2

[Sujay Parekh]

Attachment: About Firefox window too large

Comment 3

[Sujay Parekh]

Apologies if I'm using the terms menu/popup incorrectly, not sure which UI element is using what.

Comment 4

[Marius Coman [:mcoman], Ecosystem QA]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0
Firefox: 60.0a1, Build ID 20180206100151

I don't have the necessary equipment in order to test this issue so I will assign a component in order to get the engineering team involved.
Please feel free to change it if is not the correct one.

Comment 5

[Sujay Parekh]

Update: the issue does not appear in when using Firefox 58.0.2

Comment 6

[akulmehta]

This issue still appears for me on Firefox 77.0b9 (64-bit) with Windows 10. I have two displays: the main display 4k panel (set to 250% display scaling in Windows) shows the Add-ons menu options correctly, however on the 1080p panel (set to 150% display scaling in Windows) I see truncated menu panels.

This happens at least with two plugins:

1. Multi-Account Containers
2. uBlock Origin

See screenshot showing truncated uBlock Origin menu:
https://user-images.githubusercontent.com/42812604/82940084-4e731e00-9f62-11ea-8547-cd720ec8715b.png

I am not sure if I should open a new issue or is this sufficient. Please advise.

Comment 7

[Raluca Popovici, Desktop QA]

I wasn't able to reproduce this issue on Fx 86.0a1(2021-01-22) , win 10x64 with 2x external displays: a 4K (3840x2160) - scale 250% and a 1920x1080 - scale 150%.