Cannot enter date, change opening balance - Linux Mint KDE

[Petr Vorel]

Hello,

I am desperately in need of help. I have just installed GnuCash because it
seems to have the features I need but I have a lot of difficulties. I
installed it on Linux Mint KDE.

First strange thing was that I could not enter an opening balance or even
tick the box. I also cannot change the date. It either shows only
29.11.1898 or 29.11.3798 depending on which dialog I use.

Does anybody know what can be wrong please?

Petr