Crit, thank You.
It was my fault.
Inside Preferences / modify theme field when it is possible to define own css modifications it was few lines of code which broke overall look.
How to make the slash visible and not the yen sign ?
Indeed it is slash, but Yen sign is visible.
I use polish windows (maybe this is important).
Not really something I have control over so it’s not caused by the theme
Also might want to consider updating the theme, there’s a slightly newer one