Arch Linux

tsh

Member

From: Munich

Registered: 2014-07-25

Posts: 47

Website

[SOLVED] UI Fonts not rendering in Firefox and Thunderbird

Hi,

I updated my ArchLinux installation after a 12 month hiatus and found that Firefox and Thunderbird do not render fonts correctly.

I first thought it is related to GNOME and X11 issues that I read in the forums lately, but in my case Firefox and Thunderbird are not crashing. It's just their UI fonts which are not rendered properly.

Here are two screenshots:

I tried to clear up the ~/.mozilla directory by doing

mv .mozilla .mozilla.bk

, but that didn't help.

I then downgraded Firefox from 143.0.3-1 (latest as of this writing) to 129.0-1. The UI fonts were being rendered with the old version. When upgraded to the latest, the UI fonts were missing.

I uploaded the update log to https://pastebin.com/WkTXhn4N

I'm looking for pointers on how to debug the issue.

Thanks.

Last edited by tsh (2025-10-05 12:17:04)

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 68,722

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

Errr… the screenshot isn't gnome, is it?
Does

killall firefox
MOZ_ENABLE_WAYLAND=0 firefox
killall firefox
MOZ_ENABLE_WAYLAND=1 firefox

make any difference?

If not, try to downgrade gdk-pixbuf2 to 2.44.1-3 (that version *precisely* has glycin disabled)  - do you harden the system in any way?

---

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GerBra

Forum Fellow

From: Bingen/Germany

Registered: 2007-05-10

Posts: 236

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

try to downgrade gdk-pixbuf2 to 2.44.1-3 (that version *precisely* has glycin disabled)  - do you harden the system in any way?

Seth, are you sure with 2.44.1-3 ? Or do you mean the older 2.42.12-2 version?

Cause_
https://gitlab.archlinux.org/archlinux/ … 6/PKGBUILD
still build with -D glycin=enabled

There is meanwhile a non-gylcin build in AUR based on the current gdk-pixbuf2 upstream source:
https://aur.archlinux.org/packages/gdk-pixbuf2-noglycin

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 68,722

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

2.44.1-3 != 2.44.3-1
https://gitlab.archlinux.org/archlinux/ … b2f1b9668b had glycin temporarily disabled

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

GerBra

Forum Fellow

From: Bingen/Germany

Registered: 2007-05-10

Posts: 236

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

Ups, i have to clean my glasses... ;-) Sorry

tsh

Member

From: Munich

Registered: 2014-07-25

Posts: 47

Website

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

> Errr… the screenshot isn't gnome, is it?

Yes, sorry. I made the connection as GNOME > GTK3 > Firefox. I'm using i3wm.

I tried the following:
* `MOZ_ENABLE_WAYLAND` didn't work.

I also noticed that Firefox and Thunderbird don't have this issue if I use Sway, so something is causing the rendering to fail under X11. Will try to use an Xsession and report back; I'm guessing some DPI settings were being misinterpreted.

Last edited by tsh (2025-10-04 11:31:20)

tsh

Member

From: Munich

Registered: 2014-07-25

Posts: 47

Website

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

Ah, I also got bitten: 2.44.1-3 != 2.44.3-1

I didn't have the 2.44.1-3, so I downgraded to 2.42.12-1 but that didn't help either. Will try to download it from an archive and report back.

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 68,722

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

Please post your Xorg log, https://wiki.archlinux.org/title/Xorg#General
Do you get the same w/ https://wiki.archlinux.org/title/Firefo … shoot_Mode ?
Do you get it w/

GSK_RENDERER=cairo firefox

---

How to upload text · How to boot w/o GUI · Disable Windows Fast-Start! · Fix your xinitrc

tsh

Member

From: Munich

Registered: 2014-07-25

Posts: 47

Website

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

I have isolated the problem to xsettingsd after startx on a newly created user didn't show the problem.

killall xsettingsd

fixed it.

I'm now finding out what in xsettingsd config is causing this.

tsh

Member

From: Munich

Registered: 2014-07-25

Posts: 47

Website

Re: [SOLVED] UI Fonts not rendering in Firefox and Thunderbird

So, the culprit is the following line in ~/.config/xsettingsd/xsettingsd.conf

Xft/DPI -1

Using the example config from https://wiki.archlinux.org/title/Xsetti … figuration fixed it.

I have no idea why it is set to -1. It seems -1 is the default according to https://codeberg.org/derat/xsettingsd#settings and that is breaking Firefox and Thunderbird.

firefox-129.0-1 doesn't seem to be affected by this setting; the newer versions are.

Last edited by tsh (2025-10-05 12:39:58)