Can you try to right click on Seznam skupin, and open in new tab/windows.

If you can activate debug mode before it's cool ! https://manual.limesurvey.org/Debug_mode

Let me try this locally.

Works for me in English.

Right click will show error:
"The system is unable to find the requested action survey".

I added test account for You:
address: https://dotaznik.czu.cz/
user: tester
passwd: testertester1
I created example survey "Testovaci", where the problem is visible.

Will try to reproduce it to confirm it.

Please try to reset your menu items and see if the issue still exists.

Thank You.
it's already working properly. :-)

At first I was scared, because after resetting the menu, almost everything stopped working, but after resetting the menu entries, the menu started to behave correctly.

As per the comments, will be closing the ticket.
Please add any comments in case it should be reopened.
Thanks