Variable: dired-find-subdir
dired-find-subdir is a customizable variable defined in dired-x.el.gz.
Value
nil
Documentation
If non-nil, Dired always finds a directory in a buffer of its own.
If nil, Dired finds the directory as a subdirectory in some other buffer if it is present as one.
If there are several Dired buffers for a directory, the most recently used is chosen.
Dired avoids switching to the current buffer, so that if you have
a normal and a wildcard buffer for the same directory, C-x d (dired) will
toggle between those two.
Source Code
;; Defined in /usr/src/emacs/lisp/dired-x.el.gz
(defcustom dired-find-subdir nil ; t is pretty near to DWIM...
"If non-nil, Dired always finds a directory in a buffer of its own.
If nil, Dired finds the directory as a subdirectory in some other buffer
if it is present as one.
If there are several Dired buffers for a directory, the most recently
used is chosen.
Dired avoids switching to the current buffer, so that if you have
a normal and a wildcard buffer for the same directory, \\[dired] will
toggle between those two."
:type 'boolean
:group 'dired-x)