bug#32848: 26.1; follow-mode cursor move breaks with frame-resize-pixelwise

[Eli Zaretskii]

> From: Allen Li <darkfeline@felesatra.moe>
> Date: Wed, 26 Sep 2018 15:49:15 -0700
> 
> Moving the cursor off the bottom of the window with follow-mode enabled
> doesn't move to the other window properly if frame-resize-pixelwise is
> set and a partial line is visible.

It seems like setting make-cursor-line-fully-visible to nil solves the
problem.  Could you try that for a while, and see if this has any
adverse effects?

Alan and Anders: does setting this variable to nil in buffers under
follow-mode sounds like an okay solution?  It might mean that in some
rare cases the user will see the current line only partially (only in
the last window in the group).  If you think this is OK, we could
arrange for that variable to be set locally as part of turning on
follow-mode.

A more complex solution would be to allow
make-cursor-line-fully-visible have a value that is a function, which
follow-mode will define in a way that will only allow
partially-visible current line in a window if it is not the last one
in the order returned by follow-all-followers.

Comments?