bug#21173: 25.0.50; New frames positioned off screen with multiple monitors

[martin rudalics <rudalics@gmx.at>]

 > In buffer *scratch*:
 >
 >    (setq f (make-frame '((left . -1))))
 >    #<frame emacs <at> IZSYSTEM023 015257f0>
 >
 >    (frame-parameter f 'left)
 >    3155
 >
 > The left offset of the new frame appears to be 1920 pixels too far to the right.
 > Evaluating the following form positions the frame to its expected location
 > (abutting the right edge of the right monitor):

I'm not familiar with multiple monitors.  But according to the Elisp
manual ...

`left'
      The position, in pixels, of the left (or right) edge of the frame
      with respect to the left (or right) edge of the screen.  The value
      may be:

     an integer
           A positive integer relates the left edge of the frame to the
           left edge of the screen.  A negative integer relates the
	                              ^^^^^^^^^^^^^^^^
           right frame edge to the right screen edge.

     `(+ POS)'
           This specifies the position of the left frame edge relative
           to the left screen edge.  The integer POS may be positive or
           negative; a negative value specifies a position outside the
           screen or on a monitor other than the primary one (for
           multi-monitor displays).

     `(- POS)'
           This specifies the position of the right frame edge relative
           to the right screen edge.  The integer POS may be positive or
           negative; a negative value specifies a position outside the
           screen or on a monitor other than the primary one (for
           multi-monitor displays).

... you try to the position the right edge of the frame by 1 pixel left
of the right edge of the "screen".  Didn't you get exactly that?  That
is, talking about a "left offset" in this case is misleading.  What was
your "right offset?

Simply disregard this message if you were aware of what you were doing.

martin