Subject: 24.3.50; Follow mode scrolling broken on Emacs trunk

From: Anders Lindgren <[email-masked]>
Date: Fri, 22 Nov 2013 23:23:37 +0100

Hi!

Scrolling multiple pages when Follow mode is enabled sometimes fails.

Steps to repeat:

    Emacs -Q
    C-h t
    ESC : (set-frame-size (selected-frame) 200 70) RET
    M-x follow-delete-other-windows-and-split RET
    C-c . C-v

The intent is to scroll the entire document two pages down, the left
window should still be selected (this causes Follow mode to arrange the
right window after it). Instead, the right window is selected, which causes
the left to be arranged after it, effectively undoing the scroll.

The problem seems to be sometimes intermittent, sometimes the scroll works,
sometimes it don't.

An interesting effect is that the problem only occurs when
follow-scroll-up is bound to a key. When issuing M-x follow-scroll-up
RET, the command seems to be working properly.

By the way, I'm the original author of Follow mode, even tough I haven't
touched it for many years.

Sincerely,
    Anders Lindgren

In GNU Emacs 24.3.50.11 (x86_64-apple-darwin13.0.0, NS apple-appkit-1265.00)
 of 2013-11-21 on macpro.lan
Bzr revision: 115156 [email-masked]
Windowing system distributor `Apple', version 10.3.1265
Configured using:
 `configure --with-ns'

Important settings:
  value of $LC_CTYPE: UTF-8
  locale-coding-system: utf-8-unix
  default enable-multibyte-characters: t

Major mode: Fundamental

Minor modes in effect:
  follow-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
<help-echo> C-x C-g C-h t x C-x u <escape> x f o l
l o w - d e <tab> <return> C-c . C-v <escape> x r e
p o r t - b <tab> <return>

Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
C-x C-g is undefined
Preparing tutorial ...
Undo!

Load-path shadows:
None found.

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