SUMMARY


STEPS TO REPRODUCE
1. open khelpcenter 
2. press increase/reduce button
3. window show:
The requested operation could not be completed
The khelpcenter protocol could not be started
Technical reasons: Unable to create an I-slave

Request details:
URL: khelpcenter: home
Protocol: khelpcenter
Date and time: Friday 7 February 2020 16:55:26 CET
Additional information: klauncher said: Unknown "khelpcenter" protocol.
Description:
The io-slave that provides access to the khelpcenter protocol cannot be started. This usually happens for technical reasons.
Possible causes:
klauncher could not find or start the extension that provides the protocol. This means that you may have an outdated version of the extension.
Possible solutions:
Update the software to the latest version. Your distribution should provide tools for updating the software.
Contact your IT support system, be it the system administrator or the technical support group, for further assistance.
4. After other clink in increase/decrease button appears an error window: undefined url


OBSERVED RESULT
khelpcenter show error

EXPECTED RESULT
khelpcenter works

Operating System: Arch Linux 
KDE Plasma Version: 5.17.5
KDE Frameworks Version: 5.66.0
Qt Version: 5.14.1
Kernel Version: 5.5.2-arch1-1
OS Type: 64-bit
Processors: 4 × Intel® Celeron® CPU N3450 @ 1.10GHz
Memory: 5,7 GiB