That's the maximum you will be able to achieve with version 115. But you can gain some vertical space by closing the quick filter bar when it is not in use.

Now I seem to be stuck at a minimum of 9.5 entries in the message list! How do I close the Quick Filter Bar? Will probably go back to 102.13.0 if this is not fixed soon...

> How do I close the Quick Filter Bar? Will probably go back to 102.13.0 if this is not fixed soon...

Either

• click in the filter field and hit escape
• click the "quick filter" icon

To save space you can also

• disable to menu bar - View > menu bar -- on Windows the menu bar is easily resurrected with the `alt` key
• disable the status bar - View > status bar

This didn't work to close the Search window, so apparently the Quick Filter Bar is something else. What would help me is to get rid of the whole bar above the "File Edit View Go Message" etc. bar. I would be willing to close the Menu bar if I could move all of its options, including File, into the top bar where the Search window currently is.

Try view>layout>quick filter bar to remove or re add it.

Just a reminder: you also have the hamburger menu at right side of unified bar. Using that, you would not need the menu bar.

This didn't work to close the Search window, so apparently the Quick Filter Bar is something else.

I didn't provide those instructions to get rid of the search/toolbar. I provided it to close the quick filter bar which was taking 2+ lines in both of your screen shots.

Did you not get more vertical space by disabling status bar (that is likely going away , and closing quick filter bar?

What would help me is to get rid of the whole bar above the "File Edit View Go Message" etc. bar. I would be willing to close the Menu bar if I could move all of its options, including File, into the top bar where the Search window currently is.

I recommend to take some weeks getting accustomed to having the tool bar there and see what capabilities get added.

Meanwhile on why, or what is it that you really want. Why do you want fewer lines? ...

Are you wanting lots more space for displaying message content? If so, depending on your device and screen aspect ratio, maybe View > Layout Vertical is the way to go.

Or do you just want the entire window to have less height per line - a more compressed UI overall?

Or if none of these are factors, then why do you need less that 6 lines of message list?

https://support.mozilla.org/en-US/kb/getting-started-thunderbird-main-window-supernova#w_vertical-view-layout-with-card-view shows vertical view

The developers have changed the min-height for the 'Thread Pane' which means you cannot raise the Message Pane to the same degree. It can be modified. REad info below.

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.

I'm going to give the full instructions because I do not know if people already know how to create and use a userChrome.css file.

• 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'.

The new default is 200px - I've set mine to 150px using userChrome.css

@import url("chrome://messenger/content/unifiedtoolbar/unifiedToolbarWebextensions.css");

/* Thread pane - reduce min-height*/
#threadPane {
  min-height: 150px !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

Images as guide: