I tried to hide recursion in tech tree, and to disable free recursion via mod configuration dialog, but it is still available in tech and it's free without tech.
Configuration does not work for me.
Factorio v15.33 (build 30852 x64 steam)

Thanks for the report. Quick fix: Just toggle the setting off and on again while the save is loaded and running.

thanks, short question: can I make pull request with some features? or it needs some discussion before (just visual improvements without any gameplay changes)?
(it's not ready yet, but want to know :) )

Sure you can make a pull request. If I like it I'll add it. However I'm very busy with stuff at the moment so I won't be able to review it any time soon.