2020-10-19
Operating System: openSUSE Leap 15.2
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.71.0
Qt Version: 5.12.7
Kernel Version: 5.3.18-lp152.44-default
Running:
virtualbox-guest-x11 - VirtualBox X11 drivers for mouse and video 6.1.14-lp152.2.5.1
virtualbox-guest-tools - VirtualBox guest tools 6.1.14-lp152.2.5.1
virtualbox-guest-source - Source files for virtualbox guest kernel modules 6.1.14-lp152.2.5.1


Fault Summary:
The system settings keyboard shortcuts crashed.
No reaction in the Kde gui when typing keyboard shortcuts.
Eg. KWin: "Switch to Next Desktop", "Switch to Previous Desktop";
Eg. Plasma: "Switch to Next Activity", "Switch to Previous Activity";
The fault is caused by configuring in system settings a keyboard shortcut for an additional keyboard layout.


Error Symptoms:
Configure keyboard shortcuts in system settings.
Like:
System Settings > Global Shortcuts:
Other Shortcuts > KWin > Walk Through Windows > Default: Alt+Tab

Additional fault:
Other Shortcuts > KWin > Walk Through Windows (Reverse) > Default: Alt+Shift+Backtab
The above setting should display "Alt-Shift-Tab", not Alt+Shift+Backtab.

Other Shortcuts > KWin > Walk Through Windows (Reverse) > Custom: Alt+Shift+Tab
Other Shortcuts > KWin > Switch to Next Desktop > Custom: Ctrl+Tab
Other Shortcuts > KWin > Switch to Previous Desktop > Custom: Ctrl+Shift+Tab
Other Shortcuts > Plasma > Switch to Next Activity > Custom: Meta+Tab
Other Shortcuts > Plasma > Switch to Previous Activity > Custom: Meta+Shift+Tab

Additional fault:
Keyboard > Shortcuts for Switching Layout > Alternative shortcut: Ctrl+Alt+K
Only this shortcut is displayed via the Kde plasma on-screen feedback (in the middle of the screen).

The typed key-combination appears to be sent directly to the active kde foreground window, instead of being acted upon by the kde system settings for keyboard shortcuts.

Fault Reproduction:
Configure in System Settings an additional keyboard layout and assign a keyboard shortcut.
Like:
System Settings > Hardware > Input Devices:
Keyboard > Hardware > Keyboard model: Apple | Apple Aluminium (ANSI)
Keyboard > Layouts > Add: Layout: German, Default, Label de
Keyboard > Shortcuts for Switching Layout > Main shortcuts: "Left Alt+Left Shift"
Type a configured key combination, eg. for "Switch to Next Activity".


Fault Mitigation:
Reset to Defaults in "Kde > System Settings > Hardware > Input Devices > Keyboard > Advanced > Configure keyboard options > Switching to another layout > (Left Alt+Left Shift)".

Afterwards, configure the layout keyboard switching shortcut again, if it is missing. The Kde gui may be completely unresponsive; if so, a full machine ACPI shutdown helps.
After booting the machine again, magically, all Kde keyboard shortcuts appear to function correctly.


Fault Resolution:
Fix the sources for "Kde > System Settings > Hardware > Input Devices > Keyboard > Layouts: Shortcuts for Switching Layout";
aka "Kde > System Settings > Hardware > Input Devices > Keyboard > Advanced > Configure keyboard options > Switching to another layout > (Left Alt+Left Shift)".