Taking screenshot freezes the desktop and sometimes it immediately logged out

[Ade Malsasa Akbar]

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu

My Cosmic version is:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Cosmic Cuttlefish (development branch)
Release: 18.10
Codename: cosmic

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center

My package version is:

gnome-screenshot:
  Installed: 3.30.0-1ubuntu1
  Candidate: 3.30.0-1ubuntu1
  Version table:
 *** 3.30.0-1ubuntu1 500
        500 http://id.archive.ubuntu.com/ubuntu cosmic/main amd64 Packages
        100 /var/lib/dpkg/status

3) What you expected to happen

When pressing PrintScreen key, normal GNOME Screenshot will:
- flash the screen
- take the screenshot of whole screen
- save the file in PNG format on ~/Pictures/

4) What happened instead

After freshly installing Cosmic Beta, I press PrintScreen key and then:
- it flashes the screen
- all windows lost their title bars
- no screenshot file saved
- blank screen occured, no input with mouse can be done
- I still can enter tty and reboot from it

I send this report using command line suggested at QA Tracker: '$ ubuntu-bug gnome-screenshot'.

ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: gnome-screenshot 3.30.0-1ubuntu1
ProcVersionSignature: Ubuntu 4.18.0-7.8-generic 4.18.5
Uname: Linux 4.18.0-7-generic x86_64
ApportVersion: 2.20.10-0ubuntu11
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sat Sep 29 13:16:56 2018
InstallationDate: Installed on 2018-09-29 (0 days ago)
InstallationMedia: Ubuntu 18.10 "Cosmic Cuttlefish" - Beta amd64 (20180927)
SourcePackage: gnome-screenshot
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.