Moving folders

I’m trying to tidy up my folders and inbox by moving existing folders into a new folder (to file all emails prior to a set date). I’ve created a new folder and moved all relevant folders into it, however the folders I’ve moved are still visible in the panel on left of screen, though they are now greyed out and in italics. How do I make them move completely so no longer visible there?

I’ve had the same problem. I hope someone from eM Client will tell us what to do.