1611778 - On slower machines, the "Firefox Home Content" flickers when opening/reloading about:preferences#home

Status: VERIFIED FIXED

(Firefox :: New Tab Page, defect)

Description

[Itiel]

STR:

1. Be on a somewhat slow machine
2. Open about:preferences#home -- see the "Firefox Home Content" section flickers
3. Reload and see the same thing

ER:
No flicker.

I think this happens because a margin-top: 14px; [1] rule is injected via JS.

[1] https://searchfox.org/mozilla-central/source/browser/components/newtab/lib/AboutPreferences.jsm#59-61

Comment 1

[:Gijs (he/him)]

Mardak, why is this CSS dynamically injected? Can we just add it to the "normal" CSS sheets?

Comment 2

[:Gijs (he/him)]

(moving based on metadata for https://searchfox.org/mozilla-central/source/browser/components/newtab/lib/AboutPreferences.jsm#59-61 which is doing this )

Comment 3

[Ed Lee :Mardak]

Now that newtab/ development happens directly from mozilla-central, I think it would be a good time to move this custom injected css into the normal way.

Comment 4

[Itiel]

Attachment: Bug 1611778 - Fix flickering of the "Firefox Home Content" section in about:preferences on slower machines

Comment 5

[Itiel]

The attached patch fixes this, but I'm pretty sure I didn't to this right / I missed something.
Feel free to pick this up if you'd like.

Comment 6

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

The priority flag is not set for this bug.
:thecount, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 7

[Dan Mosedale (:dmosedale, :dmose)]

:Mardak, I'm pretty sure this change doesn't block freezing the github repo. Can we remove that dep?

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6e8ad5bbe739
Fix flickering of the "Firefox Home Content" section in about:preferences on slower machines r=Mardak

Comment 9

[Oana Pop-Rus]

https://hg.mozilla.org/mozilla-central/rev/6e8ad5bbe739

Comment 10

[Ciprian Muresan [:cmuresan], Ecosystem QA]

I have verified that the issue is no longer reproducible on the latest Firefox Nightly (75.0a1, BuildID 20200220093508) using Windows 10 x64, macOS 10.14, and Arch Linux 5.3.6. The "Firefox Home Content" section no longer flickers when the about:preferences#home page is loaded or refreshed.