Alt-Key handling changed after update

[Patrick Stählin]

After the updating packages, the handling of the Alt-key changed on two machines. The Alt-Left/Right switches to the console (tty6 on Alt-Left and tty2 on Alt-Right). Also pressing Alt-F2 switches to tty2 instead of opening krunner. When switching back to the Desktop (pressing Ctrl-Alt-F1, Alt-F1 works as well...) I can see that krunner is open, so the keypress does arrive in KDE.

I have no idea what could have caused this or if this only affects kubuntu.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: plasma-desktop 4:5.12.6-0ubuntu0.1
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: KDE
Date: Thu Jul 26 19:20:21 2018
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-03-20 (1224 days ago)
InstallationMedia: Kubuntu 14.10 "Utopic Unicorn" - Release amd64 (20141022.1)
SourcePackage: plasma-desktop
UpgradeStatus: Upgraded to bionic on 2018-05-18 (68 days ago)

[Launchpad Janitor (janitor)]

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

[sasha (sashalav)]

This behaviour is not consistent and, at least for me is hard to reproduce. Once it does occur Sending laptop to sleep and then Logging back in will restore the expected behaviour. I cannot yet pinpoint the moment at which ALT-Fx start being passed to X.

[Tuomas Suutari (tuomas-suutari)]

I think this is a duplicate of #520546.