Web unread messages icon breaks with Firefox RFP turned on

(#4000) Bug Confirmed

1h agoby cloud

Reproduction steps

In about:config, enable RFP: privacy.resistFingerprinting
Log into Fluxer and wait for the unread messages icon to display

Expected behaviour

The icon should display like normal: Fluxer icon with the red and white dot.

Actual behaviour

Once the Fluxer icon updates to the unread messages icon, it fails to render and vertical bars are displayed.

Build information

Stable Web 2026.1013.223958, Linux (x64), Firefox 157.0, Locale en-US Canary Web 2026.1013.223958, Linux (x64), Firefox 157.0, Locale en-US

Platform

Web

page-refresh.jxl
303×56 | 3 kB Link to page-refresh.jxl
rfp-on.jxl
303×56 | 4 kB Link to rfp-on.jxl
rfp-off.jxl
303×56 | 4 kB Link to rfp-off.jxl
rfp-on-no-unread-messages.jxl
303×56 | 4 kB Link to rfp-on-no-unread-messages.jxl

2 comments

FullestReviewer 1 vote 1h ago

I was chatting with cloud before this was submitted and was able to reproduce it. Canary Web 2026.1013.223958, Linux (x64), Firefox 157.0, Locale en-US Just not sure if there is anything Fluxer can do about this, or if it is inevitable due to the way fingerprint resisting works.

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cloud OP1 vote 1h ago

It looks similar to how certain elements look when you block canvas permissions after the website asks for it, where that element turns into colored vertical bars. The icon renders normally when RFP is off and privacy.fingerprintingProtection (FPP) does not break it either, leading me to think it's from one of the specific RFPTargets that are not turned on in FPP

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