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Bug 1679517

Summary: Firefox fails to scale between high- and low-DPI monitors
Product: [Fedora] Fedora Reporter: Quint Guvernator <quint>
Component: firefoxAssignee: Martin Stransky <stransky>
Status: CLOSED NEXTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: unspecified    
Version: 29CC: 0xalen+redhat, anto.trande, gecko-bugs-nobody, jhorak, john.j5live, kengert, pjasicek, rhughes, rstrode, sandmann, stransky
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Hardware: x86_64   
OS: Linux   
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Last Closed: 2019-03-19 09:49:17 UTC Type: Bug
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Bug Blocks: 1054334    

Description Quint Guvernator 2019-02-21 10:12:59 UTC 
Description of problem:

Firefox on Wayland fails to scale to a higher DPI screen when a lower DPI screen is attached. Other "native" gnome apps correctly scale when switching screens, e.g. Terminal, Settings, Files.


Version-Release number of selected component (if applicable):

firefox 65.0-4.fc29
gnome-shell 3.30.2-1.fc29
linux 4.20.7-200.fc29
waylandpp 0.2.3-2.fc29


Steps to Reproduce:
1. Using a high-dpi laptop display at 200% scale, plug in a lower DPI monitor at 100% scale
2. Start Firefox


Actual results:

When Firefox windows are on the low DPI external monitory, they'll be a reasonable size. When they're on the laptop screen, they're 2x too small. The cursor, icons, etc. are all too small. The cursor returns to normal size when it leaves the window.


Expected results:

The cursor and Firefox should be visually the same (or very similar) size on the high DPI screen as they are on the low DPI screen.
Comment 1 Quint Guvernator 2019-02-21 10:14:45 UTC 
Here's another user with the same issue: https://www.reddit.com/r/firefox/comments/8sq9ri/firefox_on_hidpi_screens_linux/
Comment 2 Martin Stransky 2019-03-18 15:09:36 UTC 
Can you please test with this build https://koji.fedoraproject.org/koji/taskinfo?taskID=33603998 ? It's Firefox 66 candidate. Also I can't reproduce on Fedora 30 / FF66 - maybe it's Fedora 29 specific issue?
Comment 3 Quint Guvernator 2019-03-19 09:49:17 UTC 
(In reply to Martin Stransky from comment #2)
> Can you please test with this build
> https://koji.fedoraproject.org/koji/taskinfo?taskID=33603998 ? It's Firefox
> 66 candidate. Also I can't reproduce on Fedora 30 / FF66 - maybe it's Fedora
> 29 specific issue?

Thanks for the recommendation!

I can confirm that the firefox 66 candidate is still bad when run as the "Firefox" .desktop entry, but using the "Firefox on Wayland" launcher item installed by firefox-wayland-66.0-5.test.fc29.x86_64.rpm fixes the issue! It now scales as well as the Terminal, Settings, and Files apps.

Extension context menus and pop-ups are broken and show up at half-size but that deserves its own ticket.

Thanks again for your help!
Comment 4 Quint Guvernator 2019-03-19 10:37:05 UTC 
Created new ticket for the invisible window issue: https://bugzilla.redhat.com/show_bug.cgi?id=1690363