GNU bug report logs - #4023
mwheel.el uses (point) instead of point-before-scroll

Previous Next

Full log

Message #12 received at 4023 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Glenn Morris  <rgm <at> gnu.org>,
        gabriele balducci <balducci <at> dschgrazlin2.units.it>
Cc: 4023 <at> debbugs.gnu.org
Subject: Re: mwheel.el uses (point) instead of point-before-scroll
Date: Fri, 04 Dec 2009 21:46:36 -0500

> Just upgraded emacs to 23.1 and noted the following issue, related
> (apparently) to mwheel.el.
>
> Here is how to (hopefully) reproduce the problem.
>
> In an emacs window (under X):
>
> => set the point with mouse-1
> => select a region with mouse-3 some lines below
> => now scroll down with the mouse wheel so that the bottom of the
>    selected region scrolls `out' of the upper edge of the emacs window
>    (the highlighted region must disappear)
> => extend the region by mouse-3 again
> => paste the region with mouse-2 somewhere (e.g. in a clean buffer)
>
>     Result:
>     only the text between the *visible* top of the window and the end of
>     the region has been pasted. I.e. all works as if the beginning of
>     the selected region had moved the first line of the visible portion
>     of the buffer.
>
> This contrasts with the behavior in emacs-22.3, where extending the
> region while scrolling down with the wheel used to work as expected
> (by me): the contents of the region started from the point set with
> mouse-1 at the beginning.
>
> The (correct) behavior in 23.1 is obtained if scrolling is performed
> with the side bar, instead of the wheel (and also if the scroll with
> the wheel does not make the bottom of the region fly out of the upper
> window edge)

This change was made in response to a complaint by Glenn Morris, about
the behavior you desire:

http://lists.gnu.org/archive/html/emacs-devel/2008-04/msg00409.html

  Double-click with left mouse to select the word "tree" from "This
  directory tree...". The word "tree" is highlighted with region face.

  Scroll down with mouse-wheel so that "tree" goes off the top of the
  screen.

  Scroll back up with mouse-wheel.

  Now the region has been extended to cover a lot more text. The further
  I scroll down initially, the more is highlighted.

I have no preference for either behavior, because I don't use the mouse
wheel much.  Either way, we should probably make the scrollbar and mouse
wheel behavior consistent, though.

Glenn, what do you think?

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.