kscreenlocker shows user applications when external display is disconnected

[Ian Turner]

STEPS TO REPRODUCE:
1. Lock screen
2. Disconnect external display (if none was connected, connect one, and then disconnect it)
3. User applications are displayed on the screen for a fraction of a second, then the lock screen is displayed again.

I can produce a video showing the problem, if needed.

Hardware notes:
* HP ProBook 640 G1 connected to HP Z27 Display using DisplayPort cable.

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: libkscreenlocker5 5.16.5-0ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-46.38-generic 5.3.18
Uname: Linux 5.3.0-46-generic x86_64
ApportVersion: 2.20.11-0ubuntu8.8
Architecture: amd64
Date: Mon Apr 27 21:31:21 2020
ProcEnviron:
 LANGUAGE=
 TERM=xterm-256color
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: kscreenlocker
UpgradeStatus: Upgraded to eoan on 2020-04-21 (7 days ago)

[Scarlett Gately Moore (scarlettmoore)]

I don't have another monitor to test. Please provide video or screenshot. Also please file a bug upstream at bugs.kde.org. Thanks

[Launchpad Janitor (janitor)]

[Expired for kscreenlocker (Ubuntu) because there has been no activity for 60 days.]