Well, it seems that I've updated smth wrong and now I can't customize the appearance of Ubuntu. Everything works and looks ok with defaults, if I choose anything else the result is like on the pictures.
I believe, you're using an old incompatible theme with your updated Ubuntu.
Since, from your screenshot, you're trying to use Arc theme and Arc Flatabulous theme, I suggest to update them.
You can get the updated Arc themes and many others from Noobslab Theme PPA. Add the PPA using these commands
sudo add-apt-repository ppa:noobslab/themes sudo apt-get update
Install the themes using these commands
sudo apt-get install arc-flatabulous-theme sudo apt-get install arc-theme