Bug#857595: gnome-core: Fails to display 2nd monitor sometimes after unlocking

[Artificial Amateur]

Package: gnome-core
Version: gnome-shell
Severity: normal

Dear Maintainer,

After having the environment locked or in sleep mode the second display
sometimes will come up as black.

`Alt+F --> r` brings the second display up.





-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 4.9.0-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)