This applies to Mozilla 1.4 and Courier 0.42.2 compiled
without
--enable-workarounds-for-imap-client-bugs.
Mozilla 1.2.1 (at least on Linux) did not have the problem
described below, but in my experience
every Mozilla since 1.3 has had the problem.
With the following configuration, everything in Mozilla works properly:

However, folders are displayed as subdirectories of Inbox, as shown below:

The goal is to get folders in Mozilla to display at the root level, rather than as subfolders of Inbox. The following configuration will make that happen:

This makes folders be displayed as shown below:

However, with every version of Mozilla since 1.3, if you click on anything but Inbox, you get the following error:

The previous configuration can be partially fixed using empty quotes[1] in the "Personal namespace" field, as shown below:

But this configuration results in an annoying bug where Mozilla does not list all of the folders when you first log in, as shown here:

To get folders to display, you must click the little '-' sign by the account name twice, to close it and re-open it:


This is more than just an annoyance, because
When you log in, [Mozilla] doesn't know about any of your folders except Inbox, until you close and re-open the folder list. That wouldn't be a big deal, except that if you have filters that move mail to specific folders, they will fail and be disabled because they can't find the destination folder -- Russell Wilton (courier-users mailing list)