To reproduce, run 'emacs -Q', then:
1. Type a long line of text (enough to exhibit line-wrapping).
2. Go to the beginning of line.
C-a
3. Turn on line truncation.
M-: (setq truncate-lines t)
4. Turn on line-numbers.
M-x linum-mode
5. Move cursor forward past the right-edge of the window.
C-f ...
6. When the beginning of line scrolls out of view, the line numbers disappear.
7. Move cursor back towards the beginning of line.
C-b ...
8. Confirm that the line-numbers reappear as soon as the beginning of line is back in view.
In GNU Emacs 25.1.50.1 (x86_64-apple-darwin15.6.0, NS appkit-1404.47 Version 10.11.6 (Build 15G31))
of 2016-07-28 built on MachineCode.local
Repository revision: ec359399a47f852b4d022a30245449438e349193
Windowing system distributor 'Apple', version 10.3.1404
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Configured using:
'configure --disable-dependency-tracking --disable-silent-rules
--enable-locallisppath=/usr/local/share/emacs/site-lisp
--infodir=/usr/local/Cellar/emacs-plus/HEAD-ec35939/share/info/emacs
--prefix=/usr/local/Cellar/emacs-plus/HEAD-ec35939 --with-xml2
--without-dbus --with-gnutls --with-rsvg --with-imagemagick --with-ns
--disable-ns-self-contained'
Configured features:
JPEG RSVG IMAGEMAGICK NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS
NS
Important settings:
value of $LANG: en_US.UTF-8
locale-coding-system: utf-8-unix
Major mode: Lisp Interaction
Minor modes in effect:
tooltip-mode: t
global-eldoc-mode: t
electric-indent-mode: t
mouse-wheel-mode: t
tool-bar-mode: t
menu-bar-mode: t
file-name-shadow-mode: t
global-font-lock-mode: t
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
Load-path shadows:
None found.
Features:
(shadow sort mail-extr emacsbug message subr-x puny seq byte-opt gv
bytecomp byte-compile cl-extra help-mode cconv cl-loaddefs pcase cl-lib
dired dired-loaddefs format-spec rfc822 mml easymenu mml-sec
password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils time-date mule-util tooltip eldoc electric uniquify
ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win
ucs-normalize term/common-win tool-bar dnd fontset image regexp-opt
fringe tabulated-list newcomment elisp-mode lisp-mode prog-mode register
page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock
font-lock syntax facemenu font-core term/tty-colors frame cl-generic
cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech
european ethiopic indian cyrillic chinese charscript case-table epa-hook
jka-cmpr-hook help simple abbrev obarray minibuffer cl-preloaded nadvice
loaddefs button faces cus-face macroexp files text-properties overlay
sha1 md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote kqueue cocoa ns multi-tty
make-network-process emacs)
Memory information:
((conses 16 205473 6422)
(symbols 48 20545 0)
(miscs 40 43 141)
(strings 32 18220 6425)
(string-bytes 1 585506)
(vectors 16 34498)
(vector-slots 8 666572 7372)
(floats 8 177 13)
(intervals 56 222 0)
(buffers 976 11))