doc string of mouse-position doesn't say what X and Y are

[Drew Adams]

Here's the doc string. There is nothing here that tells you the X is
across the screen (horizontal) and Y is down the screen
(vertical). All it says is that X,Y=0,0 is at the top left.

Yes, you can look up other doc to find out what is meant by position
and character cell, but this explanation might as well be
self-contained.

Return a list (FRAME X . Y) giving the current mouse frame and position.
The position is given in character cells, where (0, 0) is the
upper-left corner.
If Emacs is running on a mouseless terminal or hasn't been programmed
to read the mouse position, it returns the selected frame for FRAME
and nil for X and Y.
If `mouse-position-function' is non-nil, `mouse-position' calls it,
passing the normal return value to that function as an argument,
and returns whatever that function returns.


In GNU Emacs 22.0.50.1 (i386-msvc-nt5.1.2600)
 of 2006-07-19 on BOS-CTHEWLAP2
X server distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-msvc (12.00)'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Dired by name

Minor modes in effect:
  encoded-kbd-mode: t
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t

Recent input:
<help-echo> <help-echo> <down-mouse-1> <mouse-1> C-h
f m o s <backspace> <backspace> o u s e - p o s i t
i o n <return> <help-echo> <help-echo> <help-echo>
<help-echo> <menu-bar> <help-menu> <report-emacs-b
ug>

Recent messages:
(C:\Emacs-22-2006-07-19-Fran\bin\emacs.exe -q --no-site-file --debug-init
C:\drews-lisp-20)
Loading encoded-kb...done
For information about the GNU Project and its goals, type C-h C-p.
Loading dired...
Loading regexp-opt...done
Loading dired...done
Loading help-fns...done
Type C-x 1 to remove help window.
Loading emacsbug...done