Re: Drag and drop patch for X, please review.

[Richard Stallman <rms@gnu.org>]

    So if the mouse travels from the menu bar, to the tool bar, to a read
    only buffer, to an ordinary buffer, and then to a dired buffer, and then
    we do the drop, Emacs must send XdndStatus messages back to the source
    with different actions in them.  Possibly we want to do private on
    the menu bar and tool bar, not accept the drop in the read only buffer,
    then send private again when entering the ordinary buffer, and then
    send the action the target suggests (move, copy) when entering the
    dired buffer so that dired acts like a file manager.

I think it is better not to try to say yes and no in different Emacs
buffers.  We should treat all of the buffer text areas in a uniform way
as regards accepting drops there.

However, the menu bars could be treated differently, since the C code
can tell whether the pointer is in a menu bar.  Likewise, maybe Emacs
could always reject drops in scroll bars, or in the echo area when the
minibuffer is inactive (or maybe always in the echo area).  The C code
can tell if a window is a minibuffer window and whether it is active.

Mode lines also would have to be treated uniformly, I guess.
Is there a useful meaning for a drop in the mode line?

Different buffers can still handle the same kind of drop in different
ways, based on local key bindings.  There's no need to look thus up
except at the end, in response to the event.

If we want dropping a file into the menu bar to open the file, then I
suggest it open the file using find-file-other-window.  While no
method is always best, that's the way users most often prefer.