bug#9609: Excessive transient region highlighting with highlight-nonselected-windows

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Wed, 02 Jun 2021 09:48:05 +0200
> Cc: 9609@debbugs.gnu.org
> 
> Glenn Morris <rgm@gnu.org> writes:
> 
> > emacs -Q --eval '(progn (setq highlight-nonselected-windows t) 
> > (transient-mark-mode -1))' -f make-frame
> >
> > Two frames open showing the *scratch* buffer, once frame has focus.
> >
> > With the mouse, click on the "n" of "notes" in the focused frame. Do
> > not release the mouse. In the other frame, a region starting or ending
> > at "n" is now selected.
> 
> I can confirm that this is still present in Emacs 28.
> 
> Pretty weird behaviour.

Probably we decided that the mouse was dragged because the coordinates
in the other window are different.  Or something like that.