Problem solved:
I deleted and installed default container again. I remember, that by installing it first, I interrupted installing process anyway, because I thought, it needs too much time... But after reboot device, container appears in list, so I thought, it's all right - but it wasn't, container wasn't installed right, but no notice appears...
Correct installing container needs about 10 - 15 minutes. You have to wait till spinning wheel disappears.
Thank you for help! It was my own mistake, but it is hard to detect it for a "normal" user...
In this case I'm happy now!
Edit: Libreoffice is not really usable, isn't it? Connect with keyboard and mouse it is e.g. not possible to save a document... Toolbar works not really... Or have I to do same special settings?