Hello Oscar,
I wasn't able to make it work. I can run it in Linux without installation by (1) modifying config_pos.ini and (2) running python3 pospro. However, I don't know which of the required packages or modules makes my Gtk client go nuts (I can no longer use the POS client from Gtk; I don't have the right traceback right now, and I would have to create a new database, configure, etc. If you need the info I would do it, but I prefer to avoid it if it's unnecessary). When I do run the Qt client which you prepared, I only get a pop-up frame to input products' names. Unfortunately, I cannot select any, because there is only a Cancel button. I was not able to resize the main frame, either. Just to make sure: I'm not complaining. I hope that this helps you further. Good luck. I hope that I can be of any help.