User option dnd-open-file-other-window has no effect

[Sven Joachim]

There is a user option, dnd-open-file-other-window, which should
control the behaviour of drag-n-dropping files onto an Emacs frame.
I customized it to t:

dnd-open-file-other-window is a variable defined in `dnd'.
Its value is t

Documentation:
If non-nil, always use find-file-other-window to open dropped files.

However, that had no effect. :-(
Using debug-on-entry for dnd-open-local-file, I got the following
debugger backtrace when drag-n-dropping a file from konqueror:

Debugger entered--entering a function:
* dnd-open-local-file(#("file:///home/sven/lynx.cfg" 0 26 (foreign-selection 
STRING)) private)
 byte-code("address@hidden @\"ƒ     A\f\"ÈÉÊ\"ˆ\nA‰„*Ƈ" 
[dnd-protocol-alist bf --cl-dolist-temp-- uri action ret nil string-match throw done t] 4)
 dnd-handle-one-url(#<window 48 on dnd-open-file-other-window> private 
#("file:///home/sven/lynx.cfg" 0 26 (foreign-selection STRING)))
 x-dnd-handle-uri-list(#<window 48 on dnd-open-file-other-window> private 
#("file:///home/sven/lynx.cfg
\n" 0 29 (foreign-selection STRING)))
 byte-code("Æ	\"‰AÇ\f!‰ÈH‰:ƒ!É8‚'Ê `ËÌF)Ì8)…™Í!ƒ‰Î!ƒ‰Ï‰:ƒVÉ8‚\\Ê `ËÌF)È8†zÉ8:address@hidden)bˆ#)‚™ÐÑ\f!ˆ#)-‡" 

[type x-dnd-types-alist type-info handler frame state assoc 
x-dnd-get-state-for-frame 5 1 selected-window (0 . 0) 0 windowp window-live-p 
nil t
select-frame action event position w dnd-open-file-other-window window data] 5)
 x-dnd-drop-data((drag-n-drop (#<window 48 on dnd-open-file-other-window> 1035 (61 . 478) 
0 nil 1035 (6 . 31) nil (61 . 13) (10 . 15)) ["XdndDrop"
#<frame Emacs: dnd-open-file-other-window 0x85e0d28> 32 [... 0 ... 0 0]]) #<frame 
Emacs: dnd-open-file-other-window 0x85e0d28> #<window 48 on
dnd-open-file-other-window> #("file:///home/sven/lynx.cfg
\n" 0 29 (foreign-selection STRING)) "text/uri-list")
 byte-code("Ä     \nÅ\n!%‡" [event frame window value x-dnd-drop-data 
x-dnd-current-type] 7)
 x-dnd-handle-xdnd((drag-n-drop (#<window 48 on dnd-open-file-other-window> 1035 (61 . 
478) 0 nil 1035 (6 . 31) nil (61 . 13) (10 . 15)) ["XdndDrop"
#<frame Emacs: dnd-open-file-other-window 0x85e0d28> 32 [... 0 ... 0 0]]) #<frame 
Emacs: dnd-open-file-other-window 0x85e0d28> #<window 48 on
dnd-open-file-other-window> "XdndDrop" 32 [(192 . 896) 0 (223 . 30889) 0 0])
 x-dnd-handle-drag-n-drop-event((drag-n-drop (#<window 48 on 
dnd-open-file-other-window> 1035 (61 . 478) 0 nil 1035 (6 . 31) nil (61 . 13) (10 
. 15))
["XdndDrop" #<frame Emacs: dnd-open-file-other-window 0x85e0d28> 32 [... 0 ... 
0 0]]))
 call-interactively(x-dnd-handle-drag-n-drop-event)

And inside the debugger, dnd-open-file-other-window is nil.

It seems the function x-dnd-drop-data overwrites it temporarily, it
contains the code:

     [...]
     (if (and (windowp w) (window-live-p w))
          ;; If dropping in a window, open files in that window rather
          ;; than in a new widow.     [widow, huh! Sven.]
          (let ((dnd-open-file-other-window nil))
            (goto-char (posn-point (event-start event)))
            (funcall handler window action data))
        (let ((dnd-open-file-other-window t))  ;; Dropping on non-window.
     [...]


Meanwhile, the Emacs manual is also quite funny. It states in section
25.15, Drag and Drop:

  Dropping a file normally visits it in the window you drop it on.  If
you prefer to visit the file in a new window in such cases, customize
the variable `x-dnd-open-file-other-window'.

But the variable `x-dnd-open-file-other-window' does not exist. :-(

I noticed this misbehaviour in Emacs version

GNU Emacs 22.0.50.1 (i486-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
of 2005-09-30 on debian, modified by Debian
X server distributor `The X.Org Foundation', version 11.0.60802000