Thanks for providing additional details, usernestor-ale. I'm here to help figure out why the class column is empty.

Let's determine if this has something to do with your browser's cache. Too much cache can cause unusual behaviors in the program. To clear this out, try using a private browser to see if the class column is still empty. 

Please check out these keyboard shortcuts:

• For Chrome press Ctrl+Shift+N.
• For Firefox, press Ctrl+Shift+P.
• For Safari, hold down Command+Shift+N.

If it works, I'd recommend clearing your main browser's cache. This is to start fresh. Otherwise, try using other supported browsers. 

Please let me know how the steps work. I want to make sure everything is taken care of for you.