Hello,
when I start a new plasma session keyboard does not work on kde applications (panel, konsole, and so on).
Killing and restarting the app fixes it.
It is a famous bug:
https://askubuntu.com/questions/838613/keyboard-not-working-properly-in-kde-after-upgrade-to-kubuntu-16-10

People have solved it uninstalling and installing packages.
In my case their solutions do not work for me!
But I have discovered that, if I create a new user and log in with that user there is no bug.
So some of the kde configurations files in my home are causing that bug.
How can I identiy them?
Can you help me?
Thanks,
Mario