1866588 - sometimes font size increases on Google search results page

Status: NEW

(Core :: Layout: Text and Fonts, defect)

Description

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Firefox 120.0 on Windows 10, not observed with 119.0.1, 121.0a1 and 122.0a1.

Three times I have observed the font size on a Google search results page being larger than usual. The last time it increased during scrolling.

The location bar shows no zoom factor (like it hides it for 100%).

The same url opened again in a new tab used the default font size.

Differences for the font of the page title shown in the font inspector:

• font size: default 20px, altered: 22px
• line height: default 1.3, altered: 1.3636

A search did not find the issue at https://webcompat.com/

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Firefox::Address Bar' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Daniel Bodea [:danibodea]]

Thank you for your report! Could you also tell us which operating system was used when observing this issue? Is there anything else that might be worth mentioning about this issue? Does the problem resolve itself after refreshing the page or after restart? Did you notice the font change on any other webpage?

Comment 3

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

(In reply to Daniel Bodea [:danibodea] from comment #2)

Thank you for your report! Could you also tell us which operating system was used when observing this issue?

Hi, it's Windows 10 (see comment 0).

Does the problem resolve itself after refreshing the page or after restart?

A reload fixes this.

Did you notice the font change on any other webpage?

I am not sure if I observed it on Youtube.

This might be related to scrolling down and switching to scrolling up (with the mousewheel). I cannot reproduce it on purpose but sometimes see it multiple times per day, also with Firefox 121.0.

Comment 4

[Jonathan Kew [:jfkthame]]

This doesn't sound like a Layout issue. Given that the Inspector shows (comment 0) that the CSS properties have actually been altered, I think we're rendering the (altered) page correctly.

My guess is that there's something happening at the front-end/UX level whereby a gesture intended to scroll is instead causing the content to be zoomed.

Sebastian, do you have the Zoom text only option enabled in Preferences / General (or browser.zoom.full set to false in about:config)? If so, I believe a "zoom" factor will show up as a modification of the computed values of font-size and line-height.

Comment 5

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

do you have the Zoom text only option enabled in Preferences / General (or browser.zoom.full set to false in about:config)?

No, it's set to true (the default value).

Comment 6

[Daniel Bodea [:danibodea]]

I can't seem to reproduce this issue in Firefox Release v120.0 in Windows 10 after extended attempts.
Could you provide some more information?

1. Do you use any add-ons that might influence web content font?
2. Does this issue still reproduce in a newly created profile? (info)
3. Could you provide about:support information in the hope that some leads of the cause would be uncovered?
4. Does not reproduce in the current latest release version?

Thank you.

Comment 7

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Attachment: aboutSupport - random font size increase for google search.txt

1. Do you use any add-ons that might influence web content font?

No.

2. Does this issue still reproduce in a newly created profile? (info)

Yes, with Firefox 121.0 and 121.0.1 on every third attempt (search + scrolling). I don't manage to trigger the issue with Nightly.

3. Could you provide about:support information in the hope that some leads of the cause would be uncovered?

4. Does not reproduce in the current latest release version?
   Reproduces with 121.0.1 but not with 123.0a1 Nightly.

Comment 8

[Emilio Cobos Álvarez [:emilio]]

Can't repro either (but on Linux). Could you attach an screenshot of the altered rendering, and the rules that are applied to it from the inspector? Ideally also in the non-altered rendering.

That'd hopefully provide some info to figure this out.

Comment 9

[Emilio Cobos Álvarez [:emilio]]

Alternatively if you'd be willing to meet with me next week and share the screen we could debug it live, lmk / send me an invite if so :)

Comment 10

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Attachment: google search results - results screenshots.png

Comment 11

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

Attachment: google search results - style differences.png

Let's meet next week if this information is insufficient.

Comment 12

[Emilio Cobos Álvarez [:emilio]]

That stylesheet seems controlled by the google page. I do see that stylesheet changing when I scroll, but the sizes don't change.

Sebastian, is there something in your configuration (minimum font size, default font, or something like that) that might be uncommon?

Comment 13

[Emilio Cobos Álvarez [:emilio]]

Does the build where you see this have a different language than nightly (which presumably is en-US?) I wonder if there's something odd they're doing based on the language or so.

Comment 14

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

It's reproducible with new profiles for Firefox release, and I am not aware of font changes configured it. Both Release and Nightly are in en-US but the OS is set to "de" (German).

What I do remember is when the machine got set up and LibreOffice installed, this deteriorated the rendering of some fonts.

The Browser Toolbox's shows nothing directly related to font sizes from ua.css. h3 has 1em set for margin-block-start/end, the other rules are not active (applies to default and with issue). Thanks for taking the time.