Regression in keyboard shortcut to switch keyboard layout

[david]

I use the 'Keyboard' section in the Kubuntu System Settings to set my shortcut for switching keyboard layouts to the (pre-defined) setting "Left Ctrl+Left Shift". Up until Kubuntu 16.10 the behavior of this shortcut was as follows: When pressing both the left control and left shift key together and then releasing them again without pressing any other keys the keyboard layout would switch when the keys were released.
If, while control and shift were pressed any other key was pressed, the keyboard would not switch, but the corresponding key combination would be handled by the active window.
This is the expected, and in my opinion correct behavior.

Since Kubuntu 17.04 this behavior has changed: Now, the keyboard layout is switched as soon as I press the second one of the control and shift key down, before I even release them. This makes it impossible to use any key combo that includes the left shift and left control keys.
If I press another key while control and shift are still depressed, it will register a key press in the switched layout, plus only the modifier key I switched first.

The behavior is the same on a fresh installation and on a system upgraded from Kubuntu 16.10.

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: plasma-desktop 4:5.9.4-0ubuntu1
ProcVersionSignature: Ubuntu 4.10.0-26.30-generic 4.10.17
Uname: Linux 4.10.0-26-generic x86_64
ApportVersion: 2.20.4-0ubuntu4.1
Architecture: amd64
CurrentDesktop: KDE
Date: Mon Jul 3 22:34:35 2017
InstallationDate: Installed on 2017-06-29 (4 days ago)
InstallationMedia: Kubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
SourcePackage: plasma-desktop
UpgradeStatus: No upgrade log present (probably fresh install)

[Scarlett Gately Moore (scarlettmoore)]

This bug is very old, if it is still an issue please update the bug with information from a supported release.