bug#16647: Imprecisions with window-resizing cursors

[martin rudalics <rudalics@gmx.at>]

 > First impressions: Before splitting the window horizontally (with the
 > backwardsly-named split-window-vertically), I notice that I get the
 > changed mouse cursor indicating that I can resize the window whenever I
 > cross the mode line / bottom divider, but, in fact, I am only able to
 > use it (to increase the size of the minibuffer) when the minibuffer is
 > active. When the minibuffer is inactive, I can't resize it, yet the
 > mouse cursor still changes indicating that I can. Presumably this is a
 > bug.

I know.  I'll look into this eventually.

 > But:
 >
 >     emacs -Q
 >     M-: (set-frame-parameter nil 'bottom-divider-width 10) RET
 >     M-: (setq mouse-autoselect-window t)
 >     Drag the window divider up a few pixels (but less than one line)
 >
 > Moving the mouse cursor upwards is as before.
 >
 > Moving the mouse cursor downwards is as before except that when it
 > crosses the bottom of the bottom divider into the bottom window, the
 > focus changes to the bottom window, _but_ the resizing mouse cursor
 > continues to be displayed well in to the bottom window, but will not
 > resize the window if clicked on there -- indeed clicking on it, I can
 > select text in the bottom window while it is still displayed as a
 > resizing cursor!
 >
 > At 19:29 -0400 on Sunday 2014-02-23, E. Sabof wrote:
 >
 >> To me it looks like some code expects a full "character" movement, before it registers a change in location.
 >
 > I get a similar impression. Noticing that split-window-below is
 > documented to take only an argument that is an integral number of lines
 > (it does something when passed a decimal fraction but I can't figure out
 > what it is -- I thought it might then treat the argument as pixels but
 > that's not it), I wondered if the code assumes that the split can only
 > be an integral number of lines below the top of the window above, or
 > something, and fails to take into account a fractional position?

Try with `frame-resize-pixelwise' non-nil in your .emacs.  Maybe it's
the size hints.

martin