There is a gray "tool bar" or whatever you call it under the menu bar.

It's called the Tab bar.

It appears to be a recent message history.

No, it's not a message history. These are all messages you opened in new tabs.

There are dozens or hundreds of recent message icons on this bar - so many that it is totally useless! How do I get rid of it forever?

Go to the left most tab. Right-click the tab in the tab bar - Close Other Tabs

When I open a message the folders pane/window/whatever disappears. How do I fix it so the folders pane NEVER disappears?

May be don't open that many tabs?

To turn on the folder pane in case it is hidden: From the main menu bar: View (Alt-V) - Layout Check 'Folder Pane'

1. When I open any message the folders window/pane/bar/section/area disappears. How do I fix it so the folders section NEVER goes away?

2. Every time I open a message it remains in the "tab bar." I open dozens of messages each day, and they keep accumulating.

How do I eliminate the "tab bar?" It isn't even listed in the "View/Tool Bars" control box.

Every time I open a message it remains in the "tab bar." I open dozens of messages each day, and they keep accumulating.

The obvious thing to do would be closing tabs when you're done with the message.

I will answer with a parable.

When graphical user interfaces were first invented some smart fellow conceived the idea of drop-down menus. For him this was like opening a book, drawer or such, and when it was opened it stayed open until the user closed it. Then nested menus were invented, and they stayed open until closed, even when other menus were opened or programs/functions were executed. The user had to go back and close them all!

Then someone much smarter than the programmer (who knew nothing of how non-programmers would use the software) explained that ordinary people would not want to have to close all the menus after the desired function was achieved. Duh! That was over 40 years ago.

In a similar way, people had invented automatic door closers to close doors after people went through. And even with the newer automatic door openers the doors closed automatically after then "users" had passed. You used to have to open elevator doors to enter the elevator, and then have to close the door after you entered. Then some smart fellow invented the automatic door. All of that was over half a century ago.

Do you understand the parable?

For me, every message in my in box window is "open" for me to read, but only the header is visible. I delete the obvious spam without opening it. To see the message content I click on the header to open the message window. After I have read the message I either delete it, move it to one of my personal folders, or move on to another message. In every case any of these actions "closes" the message for me. I want the message window to close automatically. I don't want a bunch of useless "tabs" accumulating on a useless "tab bar!" Who in their right mind would??

The "tab bar" and the idiotic idea that I should have to "close" messages is a pain in the posterior.

How do I eliminate the tab bar permanently?