Download folder don't refresh

When i extract a rar o zip in donwload folder, the folder with the extracted files don't appear. I have to refresh. It occours only in my donwload folder, not in desktop or other folder. I've windows 8.1 italian. Thanks.

I get the same problem in Win7 x64 occasionally.
It seems to happen to me if I have had the same windows explorer session open for a long time.
I close explorer and open a new one and it's better.