1629607 - Text is blurry/weird in sidebar on macOS subpixel anti-aliasing enabled for fonts on external displays via Deeper.app

Status: UNCONFIRMED

(Core :: Graphics, defect, P3)

Description

[jvisser]

Attachment: TBvsAppleMail.png

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:75.0) Gecko/20100101 Firefox/75.0

Steps to reproduce:

Open Thunderbird on macOS, focus and unfocus the application

Actual results:

The text in the sidebar is blurry/weird

Expected results:

The text should be crisp. See the image attached for how it should be, with Apple Mail as the counter-example.

Comment 1

[Firefox Bug Husbandry Bot]

Resetting severity to default of --.

Comment 2

[Wayne Mery (:wsmwk)]

Eckard, can you see this?

Comment 3

[Eckard Berberich]

Attachment: Thunderbird folderpane focussed

Comment 4

[Eckard Berberich]

I can't reproduce this issue in TB 76.0b1 running macOS 10.14.6

Comment 5

[Wayne Mery (:wsmwk)]

Is this on a laptop / monitor?

I also don't see it on my macbook air with 10.15.4

Comment 6

[jvisser]

I've found out what causes it: enabling subpixel anti-aliasing (for fonts) on external displays via Deeper.app (which toggles a certain defaults write key, though whether it is defaults write -g CGFontRenderingFontSmoothingDisabled -bool NO, defaults -currentHost write -globalDomain AppleFontSmoothing -int 1 or both of those I am not sure.
Other apps do not have this issue so I do know it must be some funky interaction Thunderbird has with this setting.

Comment 7

[Firefox Bug Husbandry Bot]

Because this bug's Severity has not been changed from the default since it was filed, and it's Priority is -- (Backlog,) indicating it has has not been previously triaged, the bug's Severity is being updated to -- (default, untriaged.)

Comment 8

[Wayne Mery (:wsmwk)]

Over to graphics

Comment 9

[Jeff Muizelaar [:jrmuizel]]

Can you reproduce this in Firefox?

Comment 10

[jvisser]

On 78.0.2 I cannot. I'm trying to figure out how to attach a screenshot in a comment..

Comment 11

[jvisser]

Attachment: firefox78.0.2.png

This is with the light theme and font smoothing enabled via Deeper.app (which sets the aforementioned keys).