Mac Forum / Applications / Eudora / July 2006

The simplest way is to set up your own windows; for instance, open the
Window->Mailboxes window, and size and place it where you like. Don't
close it, and it will be there the next time you open Eudora. Using that
window you directly open any mailbox, or drag and drop messages into
whatever mailbox you prefer. So that's one element of the single plane
window. And by clicking in the list of mailboxes you can select In, Out,
Trash, anything you want to display in list view, in a window for which
you select the size, and which will retain its size and position.

This gets very close to a single pane display, except that because it's
under your control, it's better. At least that's my belief...

And of course that control is very Mac-like.

Open a mailbox, click the green dot in the upper left (to expand it to
the largest useful size.) Use the little double-arrow square at the
right end of the  divider between the message list and the message
preview pane to move it up and make the preview pane large enough so
that you can use it instead of opening new message windows. Use the blue
drawer icon at the right end of the message list header to open the
mailbox "drawer" that lets you switch mailboxes without switching
windows. Use the Mailbox Display section of the Settings window to
adjust how the preview pane acts. If you don't ever open messages in
their own windows, you probably want the Content Concentrator off and to
have messages marked read after they are viewed in the preview area.

They're only separate if you want them separate (if you double-click on
a message a separate window opens). In the Mac version it's very simple
to have everything in a single split-pane. If you haven't already done
so, click the triangle on the left/bottom of the list of messages.
You'll still have one windo--but with messages on top and the message
you're viewing on the bottom. Click (don't double-click) into a message
in the list of message and you'll see he complete message in the bottom
pane. To see messages from other mailboxes (In, Out, Trash, Junk and any
mailboxes you create) click the *drawer* symbol (top right corner, brown
drawer icon) or choose Drawer under the Window menu. (Click again to
close the drawer.) bClick on any mailbox and all its messages will show
in your split-pane view. Consult the Help menu for the basics or choose
"Online Manual" in the Help manual for more extensive instructions.  I
think you'll find, after using the Mac version for a while, that it's so
much nicer-looking and easier to use than the Windows version!

FWIW, I find such separation far superior to 'paned' views. Others have
explained how to use a paned view if you really want it, but I would
suggest that the "not liking" bit may well be due to simply not being
*used* to it -- that giving it some time to get used to it is worth it
(if only because "one window per document" is how the Mac and Mac apps
work in general, so even when you change one app to a paned view,
there'll still be the others).