Windows 10 will reach EOS (end of support) on October 14, 2025. For more information, see this article.

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.

ఇంకా తెలుసుకోండి

How do I reduce font size for mail headers?

  • 8 ప్రత్యుత్తరాలు
  • 0 ఈ సమస్యలు కలిగి ఉన్నాయి
  • 48 వీక్షణలు
  • చివరి సమాధానమిచ్చినది ajt1047

more options

Thunderbird 128.14.0esr on Debian 13 KDE. Email is in Classic View.

The mail headers take up far too much space.

Here's an example of the problem: http://map.atownsend.org.uk/tmp/Screenshot_20250829_150825_2.png . As you can see, about 50% of the UI is taken up by headers. I like the general layout (tree at the left, not included in screenshot, list of messages above and the message itself below) and I like the contents of the headers (I don't want to display fewer; I'd just like them to take up less space).

Changing the font via edit / settings / font / size has no effect on the headers (it may be changing the size of the text within the message, but I can't really see enough of that to be sure).

How do I change the font within the headers to a different, smaller, value?

Thunderbird 128.14.0esr on Debian 13 KDE. Email is in Classic View. The mail headers take up far too much space. Here's an example of the problem: http://map.atownsend.org.uk/tmp/Screenshot_20250829_150825_2.png . As you can see, about 50% of the UI is taken up by headers. I like the general layout (tree at the left, not included in screenshot, list of messages above and the message itself below) and I like the contents of the headers (I don't want to display fewer; I'd just like them to take up less space). Changing the font via edit / settings / font / size has no effect on the headers (it may be changing the size of the text within the message, but I can't really see enough of that to be sure). How do I change the font within the headers to a different, smaller, value?
జోడించిన స్క్రీన్షాట్లు

ఎంపిక చేసిన పరిష్కారం

Thunderbird provides ways to increase/decrease overall font size in the general UI and also the ability to independently control font size in Message PAne and Write message and if necessary override content in received mail. Most people find that is all they require. Infact you are the first I've come across that wants a completely different size for font in the Message Header.

As requested here follows full instructions:

First: Please check in Thunderbird to see if a setting needs switching on.

  • Settings > General
  • Scroll to bottom and click on 'Config Editor' button
  • In search type : legacy
  • look for this line: toolkit.legacyUserProfileCustomizations.stylesheets
  • If it is set as 'false' :
  • click on the far right arrow type icon to toggle from 'false' to say 'TRUE'

Now Do this: In Thunderbird

  • Help > Troubleshooting Information
  • in 'Application Basics' - Profile Folders - click on 'Open Folder'

A new window opens showing the contents of your profile name folder.

  • Exit Thunderbird now. This is important.
  • In the 'profile name ' folder create a new folder and call it 'chrome'. The spelling is important - note it is all lower case.
  • Then open a simple text editor program such as 'Notepad'.
  • Copy all the text between the lines below and paste it into 'Notepad'.

note: the font size in the code is set up as 12px but if you want 14px etc then just modifiy the number.


/*  Alters Message Header font size*/

.message-header-container {
  padding: 3px;

  @media (max-width: 768px) {
    padding: 6px;
    font-size:  12px !important;
  }
}


  • Save the file as 'userChrome.css' - note the spelling of this is important - all lower case except the C.
  • Save it in the 'chrome' folder. - see attached image as guide.

Check that file really is called 'userChrome.css' and not 'userChrome.css.txt' - it has to be saved as a Cascading Style Sheet (css) and not a text document. So if you see 'userChrome.css.txt' - no problem - just rename it by removing the .txt - you will get ask are you sure as it may effect things - just say yes because you really do want to do it.

Start Thunderbird

I've included a couple of images to help as a guide.

ఈ సందర్భంలో ఈ సమాధానం చదవండి 👍 1

ప్రత్యుత్తరాలన్నీ (8)

more options

While it doesn't answer the core question, some of the options hidden behind "more" to the right of reply, forward etc. do help.

The descriptions for some of those are wrong (for example "show sender's profile picture" changes the layout even when there is no profile picture; "show sender's full address" does not show any different text but _does_ change the font used), but fiddling about with these can reduce the space for headers. The one that actually does change a font size ("large subject") unfortunately reduces the size of the most useful piece of information there.

ఉపయోగపడిందా?

more options

A good starting point would be to use the view menu to change the headers to Normal from all. Less lines devoted to headers.

You might also want to look at this addon https://addons.thunderbird.net/en-US/thunderbird/addon/compact-headers/?src=search

ఉపయోగపడిందా?

more options

Thanks - "view / headers" is already set at "normal" rather than "all". I did briefly try the "compact headers" but it seems to have no effect, so I uninstalled it.

ఉపయోగపడిందా?

more options

The general font size in the Message header looks like it's the same font size as used in the Message List.

To reduce the font size of UI - Folder Pane, Message List, Menus and Message Header font size smaller you can use:

  • Menu app icon (3 lines) > Font Size - click on the - icon to reduce. Repeat the click until all is as desired.

Content of email and emails you compose can be increased - so different from the general UI as mentioned above via:

  • Settings > General
  • Language & Appearance
  • click on 'Advanced'
  • Increase the size for 'Proportional - Sans Serif' and possibly also the 'Minimum' - but not so it's greater than the Proportional size. This would need to done for both Fonts for 'Latin' and 'Other Writing Systems'


I have found a way of altering the font size for everything in the entire Message Header and that includes the font on the buttons as well, but I did use a 'userChrome.css' file to achieve it.

I have no idea what size font you use in the Menu icon > Font size - so as an example let's assume it's 16px and you want all the Message Header font size to be 12px This is the code I used - it's everything between the lines:


.message-header-container {
  padding: 3px;

  @media (max-width: 768px) {
    padding: 6px;
    font-size:  12px !important;
  }
}


if you need to have full instructions on creating the 'userChrome.css' file then please ask and I can provide it.

ఉపయోగపడిందా?

more options

Note: it's still possible to have a larger font for Subject, you do that via 'More' > 'Customise' and select the option for 'Large Subject' and it will override the userChrome.css font size.

ఉపయోగపడిందా?

more options

> Menu app icon (3 lines) > Font Size - click on the - icon to reduce. Repeat the click until all is as desired.

I had no idea that was there. It's on the menu bar too (view / font size / reduce). That changes the size of all text within the Thunderbird UI (not just the message headers).

> if you need to have full instructions on creating the 'userChrome.css' file then please ask and I can provide it.

Yes please - searching https://support.mozilla.org/en-US/questions/1532451?utm_campaign=questions-reply&utm_source=notification&utm_medium=email#search for "userchrome.css thunderbird" gives, in order:

  • userChrome.css and .js and userContent are unsupported (unhelpful)
  • Firefox advanced customization and configuration options (surely irrelevant)
  • Thunderbird 128 Nebula FAQ (does that apply to my version? How would I know?)

To be honest I'd expect options for changing font size to be in the UI accessible via the menus, not edited via an external stylesheet, but I guess we are where we are.

ఉపయోగపడిందా?

more options

ఎంపిక చేసిన పరిష్కారం

Thunderbird provides ways to increase/decrease overall font size in the general UI and also the ability to independently control font size in Message PAne and Write message and if necessary override content in received mail. Most people find that is all they require. Infact you are the first I've come across that wants a completely different size for font in the Message Header.

As requested here follows full instructions:

First: Please check in Thunderbird to see if a setting needs switching on.

  • Settings > General
  • Scroll to bottom and click on 'Config Editor' button
  • In search type : legacy
  • look for this line: toolkit.legacyUserProfileCustomizations.stylesheets
  • If it is set as 'false' :
  • click on the far right arrow type icon to toggle from 'false' to say 'TRUE'

Now Do this: In Thunderbird

  • Help > Troubleshooting Information
  • in 'Application Basics' - Profile Folders - click on 'Open Folder'

A new window opens showing the contents of your profile name folder.

  • Exit Thunderbird now. This is important.
  • In the 'profile name ' folder create a new folder and call it 'chrome'. The spelling is important - note it is all lower case.
  • Then open a simple text editor program such as 'Notepad'.
  • Copy all the text between the lines below and paste it into 'Notepad'.

note: the font size in the code is set up as 12px but if you want 14px etc then just modifiy the number.


/*  Alters Message Header font size*/

.message-header-container {
  padding: 3px;

  @media (max-width: 768px) {
    padding: 6px;
    font-size:  12px !important;
  }
}


  • Save the file as 'userChrome.css' - note the spelling of this is important - all lower case except the C.
  • Save it in the 'chrome' folder. - see attached image as guide.

Check that file really is called 'userChrome.css' and not 'userChrome.css.txt' - it has to be saved as a Cascading Style Sheet (css) and not a text document. So if you see 'userChrome.css.txt' - no problem - just rename it by removing the .txt - you will get ask are you sure as it may effect things - just say yes because you really do want to do it.

Start Thunderbird

I've included a couple of images to help as a guide.

ఉపయోగపడిందా?

more options

Thanks - what actually worked was this in userChrome.css:

.message-header-container {

   row-gap: 1px  !important;
   font-size:  12px !important;

}

As mentioned the "font-size" can be varied, "row-gap" helps as well. Putting it in an "@media" section didn't work. On Linux this was in ~/.thunderbird/aembqkus.default-default/chrome/userChrome.css , and ~/.thunderbird/profiles.ini had the name of the default profile in it (slightly different layout to your Windows example). https://support.mozilla.org/gl/questions/1429674 was also helpful here.

ఉపయోగపడిందా?

ఒక ప్రశ్న అడగండి

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