1377820 - FIrefox doesn't remember zoom level, if privacy.resistFingerprinting is enabled

Status: RESOLVED INVALID

(Core :: Layout, defect, P3)

Description

[dumb.n.base+github]

User Agent: Mozilla/5.0 (Windows NT 6.1; rv:50.0) Gecko/20100101 Firefox/50.0
Build ID: 20100101

Steps to reproduce:

The last few builds of nightly, since about the last week of June, seem to have the bug where custom zoom levels are not saved and applied to new tabs on the same domain. The strange thing is, I've only noticed the behavior on sites using Gazelle (https://github.com/WhatCD/Gazelle ).

Steps to reproduce: Go to site using Gazelle framework. Set custom zoom level. Open new tab (closing old one is not required to trigger, doesn't seem to matter), see that zoom level is 100% (default) and not custom zoom level.


Actual results:

Above.


Expected results:

Custom zoom levels should be remembered and applied to new tabs on the same domain, a.k.a the way it's worked for as long as I can remember.

Comment 1

[dumb.n.base+github]

> User Agent: Mozilla/5.0 (Windows NT 6.1; rv:50.0) Gecko/20100101 Firefox/50.0
> Build ID: 20100101

I don't know where that came from, but I'm currently using 56.0a1 (2017-06-30) (64-bit) on Windows 7 x64

Comment 2

[dumb.n.base+github]

Actually, it doesn't seem restricted to sites with Gazelle, those are just the only sites for which the site doesn't scale well and I have to adjust the zoom, and as such were the only sites I noticed the bug on.

Just tested it with several sites, zoom levels aren't saved there either. Seems to be global, on all sites.

Comment 3

[Daniel Holbert [:dholbert]]

This works correctly for me in current Nightly (58.0a1 (2017-09-26) (64-bit)). I'm testing using http://www.example.org/ , in a fresh Firefox profile -- I visit that site, zoom in a few times with Ctrl+, then open a new tab and type in www.example.org and hit enter. That new tab ends up at the increased zoom level, as expected.

Reporter, can you still reproduce?

Comment 4

[André]

I have the same problem. FF is not saving the zoomed levels for each website.
FF56 x64 bit here.

Comment 5

[joschuaga]

I'm having the same problem since I updated to Firefox 56.0 (64 bit). I'm using Ubuntu 16.04.

Comment 6

[Daniel Holbert [:dholbert]]

Since I can't reproduce locally (in a fresh Firefox profile), I'm suspicious that there's some add-on or some toggled preference that's responsible/involved here.

For those who can reproduce: could you try creating a new Firefox profile* and see if you can still reproduce, when running with that profile?

* https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

Comment 7

[joschuaga]

I can't reproduce with another profile. I have a pretty small lists of addons and the bug didn't appear in earlier versions. Could this have to do with privacy.resistFingerprinting ? I could imagine that the zoom level could be used for fingerprinting (which sucks if it's true) and there was a change to reset every time if said option is enabled.

Comment 8

[joschuaga]

Yep, that seems to be the cause for me.

Comment 9

[Daniel Holbert [:dholbert]]

Thanks for figuring that out!

Yeah, looks like this was implemented in bug 1369357. I can definitely see zoomlevel being used as part of fingerprinting -- like your specific screen-resolution, it's something that lets sites identify you (and distinguish you from other people) on repeat visits, based on your exact saved zoom level.  And it looks like this was a specific request from the TOR browser folks (whose privacy settings we're largely trying to encode via this resistFingerprinting pref, I think) -- note the mention of "zoom" in the list of bug 1333933 comment 0.

I'll close this as INVALID then -- since, this is behaving as-intended (per bug 1369357) -- and, to the extent that there could be a "fix" that would be checked in here, it would really be to backout bug 1369357 entirely.