Comment 0 for bug 1448761

After resuming from suspend, the Xubuntu login screen does not behave properly when an external monitor is connected (see procedure for reproducing this bug below). This problem started happening after I upgraded to Xubuntu 15.04, and it never happened under the previous Xubuntu 14.10 version.

1. Connect external monitor to laptop's HDMI port.
2. Choose external monitor as the sole display to use (do not use laptop's internal display at all: no mirroring or extending).
3. Suspend the laptop (put it to sleep) by closing the lid.
4. Wake up the laptop by opening the lid.
5. The screen is now completely gray on both the external monitor and the laptop's internal display. The mouse pointer is also visible and it responds to movements from the laptop's internal touchpad.
6. Disconnect the external monitor by unplugging the HDMI cable.
7. The regular login screen now appears.
8. Reconnect the external monitor by plugging in the HDMI cable.
9. The screen is now completely gray again, just like in step 5.

Please fix this gray screen issue! Thanks for your consideration.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: lightdm-gtk-greeter 2.0.0-0ubuntu1
Uname: Linux 3.19.4-031904-generic x86_64
ApportVersion: 2.17.2-0ubuntu1
Architecture: amd64
CurrentDesktop: XFCE
Date: Sun Apr 26 12:24:08 2015
InstallationDate: Installed on 2015-02-16 (68 days ago)
InstallationMedia: Xubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
SourcePackage: lightdm-gtk-greeter
UpgradeStatus: Upgraded to vivid on 2015-04-25 (0 days ago)