1991553 - A light flash on new dark tabs when using about:blank rather than about:newtab

Status: NEW

(Firefox :: Theme, defect, P3)

Description

[izzylaif]

Attachment: White flashing on dark background

This was reported as resolved in 1714769.
I created a new profile in 143.0.1, with all settings default.
Then using dark mode, changed default tab from "Firefox home" to blank page, end every time I open a new tab there's a brief moment when the background tries to become white, like flickering. The video should describe it better than words

Comment 1

[Timothy Nikkel (:tnikkel)]

I frame by framed the video, the flash is approx rgb(50,50,50), and the darker frames in between are about rgb(30,30,30). So maybe it's just something that can be changed in the theme?

Comment 2

[Emilio Cobos Álvarez [:emilio]]

The issue is that this background matches about:newtab, but not about:blank.

Comment 3

[Dão Gottwald [:dao]]

(In reply to izzylaif from comment #0)

Created attachment 9517040 [details]
White flashing on dark background

This was reported as resolved in 1714769.

Bug 1714769 appears to be something else, are you sure this is the right bug number?

Comment 4

[Monica Chiorean]

I was able to reproduce the issue on Win11x64 using FF build 145.0a1(20251009213524).
Marking issue as new.

Comment 5

[izzylaif]

(In reply to Dão Gottwald [:dao] from comment #3)

(In reply to izzylaif from comment #0)

Created attachment 9517040 [details]
White flashing on dark background

This was reported as resolved in 1714769.

Bug 1714769 appears to be something else, are you sure this is the right bug number?

Yes we figured out it's more of a theme issue that the original bug

Comment 6

[Dão Gottwald [:dao]]

(In reply to Emilio Cobos Álvarez [:emilio] from comment #2)

The issue is that this background matches about:newtab, but not about:blank.

Not sure what controls the about:blank background but Jules says we should update that to match about:newtab.

Comment 7

[Brad Werth [:bradwerth]]

I will try to move this forward, as it has several See Alsos linking to it.

Comment 8

[Brad Werth [:bradwerth]]

(In reply to Dão Gottwald [:dao] from comment #6)

Not sure what controls the about:blank background but Jules says we should update that to match about:newtab.

It seems like this setting of the variable tabpanel-background-color is relevant -- a comment there seems to describe a similar problem.

I am less confident that I have enough knowledge to do the right thing here. I'll take myself off the Bug, post a needinfo to Dao.

Comment 10

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

The severity field for this bug is set to S4. However, the following bug duplicate has higher severity:

• Bug 2000446: S3

:jules, could you consider increasing the severity of this bug to S3?

For more information, please visit BugBot documentation.

Comment 11

[Dão Gottwald [:dao]]

(In reply to Dão Gottwald [:dao] from comment #6)

(In reply to Emilio Cobos Álvarez [:emilio] from comment #2)

The issue is that this background matches about:newtab, but not about:blank.

Not sure what controls the about:blank background but Jules says we should update that to match about:newtab.

Emilio, do you know what controls the about:blank background?

Comment 12

[Emilio Cobos Álvarez [:emilio]]

That would be here the generic dark window color.