Сам спросил, сам отвечаю:
1.
The X.Org configuration file (/etc/X11/xorg.conf) still has InputDevice entries for the mouse and keyboard, but they are ignored now because input-hotplug is used. The keyboard settings come from /etc/default/console-setup, and to change them please use "sudo dpkg-reconfigure console-setup". After that, HAL and X need to restart.
Т. е. надо в консоли выполнить sudo dpkg-reconfigure console-setup, там из пунктов меню выбрать Generic Evdev-managed keyboard
2.
After upgrading to this version, some keys might misbehave in X. Please make sure you have set the keyboard model as Generic Evdev-managed keyboard in System → Preferences → Keyboard, in the tab Layouts. If some keys still have problems, please file a bug against xkeyboard-config, and provide the output of setxkbmap -print and xkbcomp :0 - both run in the Terminal.
Аналогично лезем в меню с раскладками и выбираем Evdev-manager. У меня все заработало. Сначала делал пункт 2, кое-какие клавиши стали правильно работать, но скриншоты все равно снимались, потом пункт 1, перегрузился и все ОК.