How to Fix: Move Thunderbird Menu Bar to Top

Infopackets Reader Jim H. writes:

" Dear Dennis,

My Thunderbird just updated to version 115.3.2 (dubbed 'Supernova') and the menu layout has changed. Specifically, the Menu Bar (which I previously enabled) is now no longer at the very top - it's below another menu. I prefer to have the Menu Bar at the very top of Thunderbird. Any idea how to fix this? "

My response:

I have also noticed this unwelcomed change and found a few articles describing the process that were overly complicated or missing information. I've decided to simplify it with my own instructions.

How to Fix: Move Thunderbird Menu Bar to Top

Here's how to fix it with as fewest steps as possible:

1. Open Thunderbird.
    
2. Make sure the Menu Bar is enabled (it should already be enabled if you've been using it previously). If it's not: right click at the top of Thunderbird and place a check mark beside "Menu Bar".
    
3. From the Menu Bar, click Tools -> Settings. A new tabbed window will appear inside Thunderbird. Near the top right hand corner, you'll see an input field that says "Find in Settings". Click inside that and type in "about:config" (no quotes). Within a few seconds, you should see an option for "Config Editor" below the search results; click it.
    
4. A new tabbed window will appear called "Advanced Preferences" with yet another input field. Inside that field, copy and paste the following: "toolkit.legacyUserProfileCustomizations.stylesheets" (no quotes). By default, the toolkit.legacyUserProfileCustomizations.stylesheets setting will have a "False" value. Double click on it and change it to "True". Make sure it's True before proceeding onto the next step.
    
5. Next, open your Thunderbird profile folder. To do so: from the Menu Bar, click Help -> Troubleshooting Information. This will open a new tabbed window. Scroll down to where it says "Profile Folder" and click the "Open Folder" button. Your Thunderbird profile folder will now open in File Explorer.
    
6. Now we need to check to see if the "Chrome" folder exists inside your Thunderbird profile folder. Inside the Chrome folder should be a file called "userChrome.css".
   
   a) If the Chrome folder does NOT exist, then neither does the userChrome.css file. You will need to create both.
   
   To do so: right click in an empty area of your Thunderbird profile folder and select New -> Folder from the dialogue menu, then label it as "Chrome" without the quotes (if using Windows 11, right click and choose "Show more options", then New -> Folder). Next, click the Start menu, and type in the word "Notepad" (no quotes); wait for Notepad to appear and then click it. Paste in the following:
   
   #toolbar-menubar{order:-1 !important;}
   
   Inside Notepad, click File -> Save As. Save the file to: Your Thunderbird Profile Folder\Chrome, and save it as: userChrome.css.
   
   For example, the full path and filename should look like this when saving it under Notepad:
   
   C:\Users\UserName\AppData\Roaming\Thunderbird\Profiles\krzuq57f.default-release-1\Chrome\userChrome.css
   
   b) If the Chrome folder DOES already exist:
   
   Follow the same instructions in 6a above, but append the "#toolbar-menubar{order:-1 !important;}" to your userChrome.css file (assuming it already exists) then save it. If the Chrome folder exists but the userChrome.css does not exist, you will need to create userChrome.css using Notepad as described in 6a above.
    
7. Close and restart Thunderbird.

If you did it successfully, you should see the menu bar at the top of Thunderbird.

I hope that helps.