I have emacs behaving more or less how I want it to by using this common bit of elisp:
(defun toggle-current-window-dedication ()
(interactive)
(let* ((window (selected-window))
(dedicated (window-dedicated-p window)))
(set-window-dedicated-p window (not dedicated))
(message "Window %sdedicated to %s"
(if dedicated "no longer " "")
(buffer-name))))
(global-set-key [pause] 'toggle-current-window-dedication)
Unfortunately, dired uses the directory for the buffer name, so dedicating a dired window only dedicates it to that directory. Once you navigate up or down, it opens a new buffer in a separate window. What I would like to do is dedicate a window to a major mode (dired in this case), and have all new buffers that default to that mode prefer that window. Is this possible?
Try using your code in combination with dired-single, which will cause all dired navigation to happen within a single buffer named *dired*. In the interests of full disclosure, I wrote dired-single.