Open Bug 1729198 Opened 2 years ago Updated 1 year ago

TB ignores anti-aliasing settings of Windows 10


(Thunderbird :: Folder and Message Lists, defect)

Thunderbird 91


(Not tracked)


(Reporter: andreas.franz, Unassigned)


(Depends on 1 open bug)


User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

I have disabled anti-aliasing of fonts systemwide on Windows 10 21H1

Actual results:

Folderpane and message list shows anti-aliased fonts.

Expected results:

No anti-aliasing as set in system-settings.

Blocks: tb91found
See Also: → 1679528

Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.1.2

I'm experiencing the same erroneous behavior after upgrading from v78.14.0. Folder and message list pane now show anti-aliased fonts. Message pane is not affected.

Exactly the same problem here. Fonts are jagged and blurry after updating to 91. Please fix it, I'm having a really hard time reading anti-aliased fonts.

See Also: → 1734912
See Also: → 1730223
See Also: → 1733808
Depends on: 1724057
Ever confirmed: true
See Also: 1733808

Last TB version that is fully respecting ClearType settings on Windows 10 is v68.12.1, see here:
I am still using this version because I really hate ClearType!

I tested the latest TB version (v91.10.0), it is still not respecting ClearType settings on all controls! :(
See here:
(The controls marked with red are using CearType.)

I reported this bug 2 years ago (,
but nothing happened, it was not even confirmed! :(

Please fix this! I would like to use the latest version, but I do not want to see any ClearType texts.

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