In a fresh 'emacs -q',
whenever I highlight text with the mouse, or S-<right>, or C-spc <right?,
etc, emacs copies the text into the Windows clipboard, and I can't disable
it.  This means that I cannot highlight text in Emacs and replace it with
text previously copied from a Windows program.  I'm running on Ubuntu 18.04
on WSL using VcXsrv.  I've tried every combination of
  transient-mark-mode
  shift-selection-mode
  save-interprogram-paste-before-kill
with no success.
If I disable  select-enable-clipboard , it won't paste from the clipboard,
and setting  select-enable-primary  also doesn't seem to matter.
--Chris

In GNU Emacs 26.3 (build 2, x86_64-pc-linux-gnu, GTK+ Version 3.22.30)
 of 2019-09-16 built on lcy01-amd64-030
Windowing system distributor 'HC-Consult', version 11.0.12005001
System Description: Ubuntu 18.04.2 LTS

Recent messages:
uncompressing simple.el.gz...done
Computing differences between ediffDX5jos and simple.el.gz8D06X4 ...
Processing difference regions ... done
user-error: At end of the difference list [2 times]
Quit
mwheel-scroll: Beginning of buffer [13 times]
mwheel-scroll: End of buffer [9 times]
Composing main Info directory...
uncompressing dir.gz...done
Composing main Info directory...done

Configured using:
 'configure --build=x86_64-linux-gnu --prefix=/usr
 '--includedir=${prefix}/include' '--mandir=${prefix}/share/man'
 '--infodir=${prefix}/share/info' --sysconfdir=/etc --localstatedir=/var
 --disable-silent-rules '--libdir=${prefix}/lib/x86_64-linux-gnu'
 '--libexecdir=${prefix}/lib/x86_64-linux-gnu' --disable-maintainer-mode
 --disable-dependency-tracking --prefix=/usr --sharedstatedir=/var/lib
 --program-suffix=26 --with-modules --with-file-notification=inotify
 --with-mailutils --with-x=yes --with-x-toolkit=gtk3 --with-xwidgets
 --with-lcms2 'CFLAGS=-g -O2
 -fdebug-prefix-map=/build/emacs26-TP6iDo/emacs26-26.3~1.git96dd019=.
-fstack-protector-strong
 -Wformat -Werror=format-security -no-pie' 'CPPFLAGS=-Wdate-time
 -D_FORTIFY_SOURCE=2' 'LDFLAGS=-Wl,-Bsymbolic-functions -Wl,-z,relro
 -no-pie''

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND GPM DBUS GSETTINGS GLIB
NOTIFY LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS XWIDGETS
LIBSYSTEMD LCMS2

Important settings:
  value of $LANG: C.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Emacs-Lisp

Minor modes in effect:
  auto-insert-mode: t
  show-paren-mode: t
  global-eldoc-mode: t
  eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-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
  temp-buffer-resize-mode: t
  column-number-mode: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
/home/chris2/.emacs.d/elpa/auctex-11.90.0/tex hides ~/.emacs.d/lisp/tex
~/.emacs.d/lisp/vc-svn hides /usr/share/emacs/26.3/lisp/vc/vc-svn
/usr/share/emacs/site-lisp/dictionaries-common/ispell hides
/usr/share/emacs/26.3/lisp/textmodes/ispell
/usr/share/emacs/site-lisp/dictionaries-common/flyspell hides
/usr/share/emacs/26.3/lisp/textmodes/flyspell
~/.emacs.d/lisp/gud hides /usr/share/emacs/26.3/lisp/progmodes/gud
~/.emacs.d/lisp/morse hides /usr/share/emacs/26.3/lisp/play/morse

Features:
(shadow sort mail-extr emacsbug sendmail ediff-merg ediff-wind
ediff-diff ediff-mult ediff-help ediff-init ediff-util ediff noutline
outline pp eieio-opt view find-func cl-print apropos help-fns radix-tree
misearch multi-isearch cl-extra help-mode parse-time elec-pair
julia-local julia-repl s subr-x term disp-table ehelp finder-inf
tex-site package url-handlers server cint calc-local tex-local miscx
cal-menu calendar cal-loaddefs customx infox info helpx compilex compile
diredx gud speedbar sb-image ezimage dframe comint ansi-color warnings
find-dired ffap thingatpt url-parse auth-source eieio eieio-core
eieio-loaddefs url-vars windowx cycle-buffers editx rect bookmarks
comintx jka-compr cvs-local pcvs vc-cvs pcvs-parse pcvs-info pcvs-defs
git cl-seq cl-macs log-edit easy-mmode message rmc puny seq byte-opt
bytecomp byte-compile cconv dired dired-loaddefs format-spec rfc822 mml
mml-sec password-cache epa derived epg epg-config gnus-util rmail
rmail-loaddefs mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047
rfc2045 mm-util ietf-drums mail-prsvr mailabbrev mail-utils gmm-utils
mailheader ring pcvs-util add-log ewoc cl gv eediff vc vc-dispatcher
ediff-vers cc-ext fortran cus-edit easymenu cus-start cus-load wid-edit
cl-loaddefs cl-lib jkl advice autoinsert paren delsel time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar
dnd fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page menu-bar
rfn-eshadow isearch 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 composite charscript charprop
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 threads dbusbind
inotify lcms2 dynamic-setting system-font-setting font-render-setting
xwidget-internal move-toolbar gtk x-toolkit x multi-tty
make-network-process emacs)

Memory information:
((conses 16 416738 39072)
 (symbols 48 36151 3)
 (miscs 40 717 1331)
 (strings 32 105894 13053)
 (string-bytes 1 2684022)
 (vectors 16 32585)
 (vector-slots 8 795517 29726)
 (floats 8 104 949)
 (intervals 56 14482 40)
 (buffers 992 29))