Be careful players, when changing your equipment with right click. Sometimes the item which you replaced(the one which was equiped before) could simply disappear from your inventory[!] I don't know why or when, I had it happen with my belt on 6th floor. Also, on my stream, I confirmed that 2 other players had same problem. This is scary..
I find that if I have my inventory and character windows both open when I swap belts via right-click, it works fine. If I swap belts via right-click without my character window open, bye-bye belt.