bug#23925: 25.0.95; display broken when maximizing frame

[Roland Winkler]

After a long time I build again a more recent emacs.  Unfortunately
it gives me a rather unpleasant experience when maximizing the emacs
frame (using the maximize function of the xfce window manager):
somehow the frame is not redrawn properly, emacs seems to be unaware
of the new frame size and the minibuffer disappears completely.
Instead the desktop background is displayed in large parts of the
emacs frame.  Unmaximizing makes the problem go away.  But obviously
that is no solution.  I can provide more details if you let me know
what would be interesting.




In GNU Emacs 25.0.95.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.18.9, cairo 
version 1.14.6)
 of 2016-07-08 built on regnitz
Windowing system distributor 'The X.Org Foundation', version 11.0.11803000
System Description:     Ubuntu 16.04 LTS

Configured using:
 'configure --with-xwidgets --with-x-toolkit=gtk3 --with-cairo'

Configured features:
XPM JPEG TIFF GIF PNG RSVG CAIRO IMAGEMAGICK SOUND GPM DBUS GCONF
GSETTINGS NOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT
LIBOTF XFT ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XWIDGETS

Important settings:
  value of $LC_COLLATE: C
  value of $LANG: en_US.utf8
  value of $XMODIFIERS: 
  locale-coding-system: utf-8-unix