Hi Juraj, thanks for sending your v4 ui folder.

You don't have any modified files there from the default v4 install, so you don't need anything to be updated there.

Do a new install of v5 and just leave v5's ui folder alone, do not copy the v4 ui folder into the v5 install.

Then your Options > Grid should show the "From theme" or "Custom" options, set it to "Custom".

- Michael