Evaluating next form in scratch buffer:

    (with-help-window "TEST"
      (set-buffer standard-output)
      (cursor-sensor-mode 1)
      (insert "here"))

Results in error:

    Error in post-command-hook (cursor-sensor--detect): (args-out-of-range
354582)

Looks like cursor-sensor uses scratch's window instead of "TEST" buffer
window.

I do not remember getting such error in Emacs 26, 27

Thanks

------
In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.18.9)
 of 2019-12-25 built on wrt
Repository revision: 7c5d6a2afc6c23a7fff8456f506ee2aa2d37a3b9
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description: Ubuntu 16.04.1 LTS

Recent messages:
Mark set
Mark saved where search started
Mark set
uncompressing help.el.gz...done
Note: file is write protected
uncompressing window.el.gz...done
Note: file is write protected
Mark activated
next-line: End of buffer [2 times]
Mark set [4 times]

Configured using:
 'configure --with-modules'

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND DBUS GSETTINGS GLIB NOTIFY INOTIFY
GNUTLS LIBXML2 FREETYPE HARFBUZZ LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS
GTK3 X11 XDBE XIM MODULES THREADS JSON PDUMPER LCMS2 GMP

Important settings:
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  value of $LC_NUMERIC: ru_RU.UTF-8
  value of $LC_TIME: ru_RU.UTF-8
  value of $LANG: en_US.UTF-8
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Major mode: Lisp Interaction

Minor modes in effect:
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Load-path shadows:
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/home/lg/.emacs.d/elpa/tracking-20171210.2102/tracking
/home/lg/.emacs.d/elpa/circe-20180105.1158/shorten hides
/home/lg/.emacs.d/elpa/tracking-20171210.2102/shorten

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timer select scroll-bar mouse jit-lock font-lock syntax facemenu
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inotify lcms2 dynamic-setting system-font-setting font-render-setting
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Memory information:
((conses 16 404633 73335)
 (symbols 48 34773 1)
 (strings 32 103486 2565)
 (string-bytes 1 3713081)
 (vectors 16 48517)
 (vector-slots 8 743695 36310)
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 (intervals 56 1236 239)
 (buffers 1000 19)
 (heap 1024 38267 2970))

-- 
lg