[tlug] keyboard behavior changed

[Thomas Blasejewicz <nyuwa@example.com>]

Good morning from Hayama
I was wondering if anybody can give me some hints regarding the 
following problem.
I am using Linux Mint 19 (on an old Dell Inspiron 1545 / as an 
"experimental" machine).

Usually I do not spend much time with it, but the other day I noticed, 
that its keyboard behavior was totally off after the PC just sat several 
weeks in the corner.
Unable to figure something out, I followed the offer (presented by the 
PC) to upgrade to Mint 19.2.

Yet, the keyboard behavior is still off in multiple ways. Like:
* The keyboard icons (I use German and Japanese keyboard layouts) do NOT 
show in the system tray
* All attempts at changing the hotkey for changing input methods have failed
* While groping (typing) in the dark, somehow the switch between 
English/German, and with a little luck English/Japanese, "works"
    - however while it works in LibreOffice Writer, it does not so in Kate
* The key combination "Ctrl+Alt" opens a dialog for "Shutdown", but this 
is NOT the default shortcut. No other key combination I have tried to 
enter was accepted/works
* So far, with THIS and other machines I have at home, pressing TAB used 
to switch between any options presented on the screen,
    like in the Shutdown dialog: there are 4 options. This does not 
work either.

Most likely there are more quirks of this sort.

Is there maybe any magic command than can correct this behavior?
Thank you.
And sorry for asking such uneducated question
Thomas