The following patch to dnd.el adds support for remote files via a new
variable dnd-open-remote-file-function.
On Windows, this defaults to the new function dnd-open-unc-file, on
other platforms it is nil, giving the old behavior. If other platforms
can receive remote files by drag and drop, then appropriate methods
for accessing them can be added (perhaps via tramp).
Any objections to installing this now?
+ (defcustom dnd-open-remote-file-function
+ (if (eq system-type 'windows-nt)
+ 'dnd-open-unc-file
+ nil)
+ "The function to call when opening a file on a remote machine.
+ The function will be called with two arguments; URI and ACTION. See
+ `dnd-open-file' for details.
+ If nil, then dragging remote files into Emacs will result in an error.
+ Predefined functions are `dnd-open-unc-file', which attempts to open
+ the file using its UNC name and is the default on MS-Windows."
+ :version "22.1"
+ :type 'function
+ :group 'dnd)