It seems to be working now.
I recommend you to exclude Scriptegrator plugin scripts from being compressed.

Bye.

Which are the files I have to exclude from compression?

Hi, it depends on Core Design extension.
Easily search in source code of your page and match all paths starting with:
/plugins/system/cdscriptegrator/libraries/
path.

Bye.

Unfortunately, applied to your advice, but still tabs do not work. Web address: www.compus-net.com/index.php/internet-w-twoim-domu-cennik . Please some tips. Thank you.

Hi, your script on page are being compressed:
/t3-assets/js_4fa4c.js

Please disable the compression first.

Bye.

in the global configuration of Joomla, server tab, the option to compress pages is unchecked. Is that it?

the "JCE/global configuration/compression option" is disabled all compression too

-EDIT-

In fact, the template has been optimized scripting option. I blocked it out. Still, the tabs do not work.

Interestingly, the copy of the page compus-net.pl/index.php/internet-w-twoim-domu-cennik tabs work.

By the way scripts are not compressed. Was selected the option "join and minify" rather than compression.