Hello,

    Sometimes when I switch to another virtual desktop then come back
to emacs, the entire frame shows only the background color, no letter
or only part of the frame is visible.  This does not happen all the
time though.  I just happened to capture a screenshot (attached, I
hope the mailing server accepts it.)

Thanks,

Yuan

Here is the info:

In GNU Emacs 25.0.50.1 (x86_64-pc-linux-gnu, cairo version 1.14.2)
 of 2015-11-09
Repository revision: 0f50e5163cf747fcf18124039a82b5156a48316b
Windowing system distributor 'The X.Org Foundation', version 11.0.11604000
System Description:    NAME=Gentoo

Configured using:
 'configure --prefix=/usr --build=x86_64-pc-linux-gnu
 --host=x86_64-pc-linux-gnu --mandir=/usr/share/man
 --infodir=/usr/share/info --datadir=/usr/share --sysconfdir=/etc
 --localstatedir=/var/lib --disable-dependency-tracking
 --disable-silent-rules --libdir=/usr/lib64
 --program-suffix=-emacs-25-vcs --infodir=/usr/share/info/emacs-25-vcs
 --localstatedir=/var
 --enable-locallisppath=/etc/emacs:/usr/share/emacs/site-lisp
 --with-gameuser=:gamestat --without-compress-install
 --with-file-notification=inotify --enable-acl --with-dbus
 --with-gnutls --with-gpm --with-hesiod --with-kerberos
 --with-kerberos5 --with-xml2 --without-selinux --without-wide-int
 --with-zlib --with-sound=alsa --with-x --without-ns --without-gconf
 --without-gsettings --without-toolkit-scroll-bars --with-gif
 --with-jpeg --with-png --with-rsvg --with-tiff --with-xpm
 --with-imagemagick --with-xft --with-cairo --without-libotf
 --without-m17n-flt --with-x-toolkit=no
 GENTOO_PACKAGE=app-editors/emacs-vcs-25.0.9999-r1 EGIT_BRANCH=master
 EGIT_VERSION=0f50e5163cf747fcf18124039a82b5156a48316b 'CFLAGS=-O2
 -march=native -pipe' CPPFLAGS= 'LDFLAGS=-Wl,-O1 -Wl,--as-needed''

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO IMAGEMAGICK SOUND GPM DBUS NOTIFY ACL
GNUTLS LIBXML2 FREETYPE XFT ZLIB X11

Important settings:
  value of $LC_CTYPE: zh_CN.UTF-8
  value of $LANG: en_US.iso88591
  value of $XMODIFIERS: @im=fcitx
  locale-coding-system: utf-8-unix

Major mode: Text

Minor modes in effect:
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  diff-auto-refine-mode: t
  shell-dirtrack-mode: t
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  global-ede-mode: t
  ede-minor-mode: t
  global-semantic-mru-bookmark-mode: t
  global-semanticdb-minor-mode: t
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  global-semantic-idle-scheduler-mode: t
  global-semantic-idle-summary-mode: t
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  global-semantic-highlight-func-mode: t
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  show-paren-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
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  auto-encryption-mode: t
  auto-compression-mode: t
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  line-number-mode: t
  auto-fill-function: do-auto-fill
  abbrev-mode: t

Recent messages:
Wrote /home/ymei/Work/UltrafastImaging/TopmetalElectrodeSim/Makefile
Saving file /home/ymei/Work/UltrafastImaging/TopmetalElectrodeSim/Makefile...
Wrote /home/ymei/Work/UltrafastImaging/TopmetalElectrodeSim/Makefile
Saving file /home/ymei/Work/UltrafastImaging/TopmetalElectrodeSim/Makefile...
Wrote /home/ymei/Work/UltrafastImaging/TopmetalElectrodeSim/Makefile
next-line: End of buffer
scroll-down-command: Beginning of buffer [3 times]
previous-line: Beginning of buffer [2 times]
next-line: End of buffer [2 times]
Making completion list...
Quit

Load-path shadows:
~/.emacs.d/xref/emacs/xref hides /usr/share/emacs/25.0.50/lisp/progmodes/xref
/usr/share/emacs/site-lisp/cjk-latex/thai-word hides
/usr/share/emacs/25.0.50/lisp/language/thai-word

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format env code-pages mule custom widget hashtable-print-readable
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multi-tty make-network-process emacs)

Memory information:
((conses 16 385636 18540)
 (symbols 48 40954 0)
 (miscs 40 425 782)
 (strings 32 83221 13468)
 (string-bytes 1 2594038)
 (vectors 16 37715)
 (vector-slots 8 881298 6429)
 (floats 8 1324 371)
 (intervals 56 6404 0)
 (buffers 976 24)
 (heap 1024 37935 2670))