Going back is not a supported process and may result in problems. But The space issue tends to be a bad hidden configuration setting.

Check the Config Editor for this settings:

• Settings > General
• scroll to bottom and click on 'Config Editor' button

It opens in a new tab

• In top search type: pixels
• look for this line : layout.css.devPixelsPerPx
• default is a negative number -1.0

It should not be in bold text, if bold text then it has been altered.

• If you have anything else in that setting use the arrow icon on far right - click on it and the default is reset.

Another value to check is mail.uifontsize, what value do you see?

Please post your results

If you want the old toolbar look:

• right click in the open toolbar space at the top, pick customize - all your familiar buttons are there.
• remove the icons from the top of folder pane, the settings found in the three dots to the right of "+ New Message"

layout.css.devPixelsPerPx default is a negative number -1.0 It is -1.0 and is NOT Bold

mail.uifontsize value is 0

I have added my desired buttons to the open toolbar space, thanks.

Is there a way to make ALL the fonts larger, for my old eyes?

And of course I would like to make the inbox messages pane smaller and the actual e-mail space larger.

Thanks for your help so far, Len

Use the application menu font size entry to resize the interface.

I am basing my guess on what you are asking on "I want the main space back on the majority of the screen. Now the majority of the screen is taken up with a list of messages with only a small box on the right for the actual message." which leaves plenty of room for guessing.

Thunderbird V115 has instituted as default a "view" which has been available for more than a decade. The vertical view. This copies the outlook layout of having three columns across the screen. One with folders, the next with a list of mails and finally the actual content. Personally I find this entirely frustrating as I left the outlook fold to get away from exactly this sort of mess.

Fortunately you can still change the "View" using the > View and selecting either the wide or classic view. These two layouts have very little difference, until you enable the reading pane (f8) at which point the wide view utilises the entire bottom of the screen for email and the classic view only uses the part below the message list. The folder list reaching from the bottom to the top of the screen on the left.

Version 115 also changes the way we see emails into this new card view. I find it entirely useless as most of my email in threaded and the card view fails on that dismally. SO I have reverted to the good old list view. To change this setting one has to have the "Message header" pane enabled. > View > folder pane header. Then you can use the to switch the folder pane back to list view. Once you have done that you can again loose the folder pane header as it really only has that purpose, oh that and to show the count of messages in the folder that used to be in the status bar as the bottom of the screen.

Next go to the settings. Here search for hide and toggle the Hide system window tittle bar if that irks you. It did me after I implemented the code in this topichttps://support.mozilla.org/en-US/questions/1422908 to place the menu bar back above the toolbar where it belongs.

This new version is a pain in the backside. If they wanted to change it and it can do all things as above why not leave it looking as it was and just let idiots that want to change things change their own!!! I object to having to jump through all these hoops just to get back to where it was yesterday. As far as I am concerned there was nothing wrong with the old version. It was not broken so why change it? I won't be donating any more money as I don't agree with using it for this sort of thing.

This new version is a pain in the backside. If they wanted to change it and it can do all things as above why not leave it looking as it was and just let idiots that want to change things change their own!!! I object to having to jump through all these hoops just to get back to where it was yesterday. As far as I am concerned there was nothing wrong with the old version. It was not broken so why change it? I won't be donating any more money as I don't agree with using it for this sort of thing.

Seriously, this is support. If you have feedback, try offering it on the feedback link on the help menu, where someone involved with the development team stands a chance of hearing what you have to say.

I don't like supernova either, so that makes two of us, but it changes nothing! Your threats and promises about donations really are also a waste of your time and mine in reading it, because again it does not change anything nor does anyone that might care read your support post, because support is based on peer support. The only ones here are fellow users that may or may not agree with you, but they certainly are in no better position to influence the design decisions than you are.

Thanks for your suggestion about the feedback link which I didn't know about. I will certainly put my views on there so they know how I feel about it.

Thanks for your suggestion about the feedback link which I didn't know about. I will certainly put my views on there so they know how I feel about it.

That is why I am so frustrated with folk putting the feedback in the support forum. They are wasting their time writing it and mine reading it. So sorry if I come across as testy, but I think there are some real issue that are not getting to where they need to be aired.