When dired-x.el is loaded, some standard Dired functions from
dired.el and dired-aux.el offer additional features.
dired-add-entry obeys Dired Omit mode (see Omitting Files in Dired), if it is active. dired-find-buffer-nocreate and
dired-initial-position respect the value of
dired-find-subdir (see Miscellaneous Commands).