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dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

[SOLVED] GTK: disable characters autoreplacement in input widgets

Some character sequences in firefox address bar are automatically replaced by other glyphs. For example, when I type "->", it is replaced with

When I type "<=>", it is replaced with

Firefox 142.0.1.

This is very annoying. Is this quirk of firefox or something else system-wide? Does anyone know how to disable this "feature"?
Some time ago I faced with similar behavior in vscodium and found how to disable it in vscodium options. For firefox I found nothing yet.
Thank you in advance.

Last edited by dimich (2025-08-29 06:54:49)

Lone_Wolf

Administrator

From: Netherlands, Europe

Registered: 2005-10-04

Posts: 14,837

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

It appears to be a visual change only.

c/p to a text editor shows the original characters , deleting the last char shows the others still being there.

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dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

It appears to be a visual change only.

I understand. It is even possible to move caret in the middle of that composed "character".
But I want to disable this replacement, so looking for starting point: whether it performed by firefox itself or something else, e.g. fontconfig.

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 73,695

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

https://wiki.archlinux.org/title/Font_c … aced_fonts
But idk whether FF respects FC settings here enough
(I get the same behavior, though, so in theory I could experiment w/ this but rn I need the browser running )

Edit: doesn't look like
Gemini sugested

    #urlbar {
      -moz-font-feature-settings: "liga=0";
    }

in your userChrome.css, but doesntwork™ - stupid AI (was couched as unofficial and pot. subject to change, though)

Last edited by seth (2025-08-28 15:40:07)

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dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

    #urlbar {
      -moz-font-feature-settings: "liga=0";
    }

in your userChrome.css, but doesntwork™ - stupid AI (was couched as unofficial and pot. subject to change, though)

Modern firefox requires "toolkit.legacyUserProfileCustomizations.stylesheets = true" for userChrome.css to have effect. However, neither -moz-font-feature-settings: "liga=0"; nor font-feature-settings: "liga=0"; changes anything. Probably it should be some other feature name rather than "liga".

Just for test I changed userChrome.ccs to

#urlbar {
    font-family: "Courier New";
}

and it makes effect. Moreover, glyphs are NOT replaced in this case. It seems like this replacement is a feature set for font used by firefox in address bar (and "Find in page" bar as well). It would be helpful first to find out what this font is.

dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

Oh gosh, this is not only in firefox but in many gtk3 and gtk4 applications. For example, in any Edit widget of gtk3-demo and gtk4-demo.
Edit: updated subject.

seth

Member

From: Don't DM me only for attention

Registered: 2012-09-03

Posts: 73,695

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

~/.config/fontconfig/conf.d/99-no-ligatures.conf

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
<fontconfig>
  <description>Disable ligatures for monospaced fonts to avoid ff, fi, ffi, etc. becoming only one character wide</description>
  <match target="font">
    <edit name="fontfeatures" mode="append">
      <string>liga off</string>
      <string>dlig off</string>
      <string>calt off</string>
      <string>clig off</string>
    </edit>
  </match>
</fontconfig>

it's calt/clig (for me) - still not tested FF

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dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

Found that this feature is called "Contextual Alternative". Now I'm looking how to disable it globally and permanently.

dimich

Member

From: Kharkiv, Ukraine

Registered: 2009-11-03

Posts: 523

Re: [SOLVED] GTK: disable characters autoreplacement in input widgets

~/.config/fontconfig/conf.d/99-no-ligatures.conf

Yep, this works. Thank you!