Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Thunderbird 78.4.3 font size

  • 8 replies
  • 3 have this problem
  • 493 views
  • Last reply by Toad-Hall

more options

I have been trying to figure out a way to change the font sizes in Thunderbird 78.4.3. None of the "help" works. Font changing extensions are out of date. Help threads point to menu items that aren't there. Can't even find the "config.editor". My eyes just can't handle the small fonts anymore.What can I do?

Captain Quack.

All Replies (8)

more options

In version 78*:

  • Menu app icon (3 horizontal lines) > Options (If using MAC it's 'Preferences')
  • Select 'General' - top of left pane
  • Scroll down to the very bottom (OR type: Config into the top right 'find in options' search)
  • click on 'Config Editor' button to open 'about:config'

It will say be careful :)

  • In search type: pixels
  • Look for this line: layout.css.devPixelsPerPx
  • Double left click on that line to open the 'Enter string Value' box so you can edit the Value.

The default value will be -1.0

  • Enter a new number eg: 1.25 or 1.5 or 2.0 or 2.2
  • click on OK

the effect is immediate, so you can modify that number until it looks ok for you.

Helpful?

more options

If image in this forum question looks too small, click on the image to enlarge it.

Helpful?

more options

sorry. no config at the bottom of the page under those directions. just HTML Style at the bottom of the general page. entering config in the search box just brings up configure connection and configure offline.

Captain Quack.

Helpful?

more options

'HTML Style' is not under 'General' It is under 'Composition'. so you are not looking in the correct place. So I can assume you did not select 'General' and then scroll to the bottom, which is shown in th first image I posted.

Now I see what you did. You did this - (OR type: Config into the top right 'find in options' search) So you got a 'Search' result. In which case 'Config Editor' appears half way down on the right side.

I've added an image below to help.

Helpful?

more options

I apologize. I did have the wrong area. I found config editor and did as you suggested. that did the trick! as soon as I realized I didn't need the - in front of the number things worked out right and 2.25 is the best size for me. now I just have to remember how to do this next time I have to reinstall lol. thank you for your help even when I was being a bone head.

Captain Quack.

Helpful?

more options

Unfortunately, this is not working for me.

I am using a MacBook with an attached second monitor. Both screens with different in dpi / pixels. Changing the layout.css.devPixelsPerPx does affect the sizes – but very differently on each screen.

Therefore I need to stick with the (way too small) default font size. 

So, i am asking the question again: Why is the font setting too small in the first place? Obviously, people want to fix that. But why do we need to get a useful font-size by applying this hack?

Sorry, this is certainly not a rant – I am just wondering. And I think, it should be fixed in the shipped version of Thunderbird.

Helpful?

more options

hello97 said

Unfortunately, this is not working for me. I am using a MacBook with an attached second monitor. Both screens with different in dpi / pixels. Changing the layout.css.devPixelsPerPx does affect the sizes – but very differently on each screen. Therefore I need to stick with the (way too small) default font size.  So, i am asking the question again: Why is the font setting too small in the first place? Obviously, people want to fix that. But why do we need to get a useful font-size by applying this hack? Sorry, this is certainly not a rant – I am just wondering. And I think, it should be fixed in the shipped version of Thunderbird.


After looking into this, I came up with a solution that works for me. The task was, to make the UI readable (bigger font-sizes) on multiple screens with different sizes.

I opened the 'Config Editor' and set toolkit.legacyUserProfileCustomizations.stylesheets to true In the Thunderbirds profiles folder "xxxxxxx.default" I created the folder "chrome" inside that folder I put "userChrome.css" with following contents: (...)

I put it to github to make it easy accessible: "github.com/mjut/biggerthunderbird"

This is still something, I consider a "hack" and shouldn't be necessary in the first place. But I like the results! Thunderbird is looking a lot better now. =)

Modified by mjut

Helpful?

more options

It looks perfectly ok to me out of the box. I'm using Windows 10 OS and Display resolution 1920 x 1080.

But not all computers have the same screen resolution and not all people have the same eyesight. As you have seen first hand, the dpi setting on computer/monitor screen will effect what you see, hence the need to include a means of being able to alter Thunderbird so it can be adjusted to accomodate all those variations.

Helpful?

Ask a question

You must log in to your account to reply to posts. Please start a new question, if you do not have an account yet.