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Mij stipescams. Wy sille jo nea freegje in telefoannûmer te beljen, der in sms nei ta te stjoeren of persoanlike gegevens te dielen. Meld fertochte aktiviteit mei de opsje ‘Misbrûk melde’.

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Firefox built-in PDF viewer stuck in light mode when privacy.resistFingerprinting is enabled

Firefox PDF’s
Paul hat 1 jier lyn antwurde
Xinyue Wang
Xinyue Wang

Hi everyone,

After enabling `privacy.resistFingerprinting = true` in `about:config`, I noticed that Firefox’s built-in PDF viewer (`pdf.js`) is always displayed in **light mode**, even though my system and browser themes are both dark.

I understand that RFP forces `prefers-color-scheme: light` to prevent fingerprinting, but this also affects internal components like the PDF reader. Unfortunately, the PDF viewer doesn’t provide a manual dark mode toggle.

Is there any **official or safe workaround** that allows keeping RFP enabled while still having the PDF viewer use dark colors?

Thanks!

Hi everyone, After enabling `privacy.resistFingerprinting = true` in `about:config`, I noticed that Firefox’s built-in PDF viewer (`pdf.js`) is always displayed in **light mode**, even though my system and browser themes are both dark. I understand that RFP forces `prefers-color-scheme: light` to prevent fingerprinting, but this also affects internal components like the PDF reader. Unfortunately, the PDF viewer doesn’t provide a manual dark mode toggle. Is there any **official or safe workaround** that allows keeping RFP enabled while still having the PDF viewer use dark colors? Thanks!

Alle antwurden (1)

Paul
Paul
  • Moderator
  • Top 10-meiwurker

Hi

The fingerprinting resistance is based on presets to try to achieve that aim and may not always lead to a configuration you would prefer for browsing.

An overview of a number of the settings are at https://support.mozilla.org/en-US/kb/resist-fingerprinting and I would avoid about:config if possible.