Can someone tell me how to work with the option "delete folder only if empty" in the action "file removal"?

for example i have a folder "c:\test" wich can contain between 4 and 10 files in it. I delete with a "file removal" action 4 files. Since the folder contains between 4 and 10 files the folder c:\test could or could not be empty.
I check the "delete folder only if empty" option to delete the folder only when it is empty.

Eventough the folder is empty the folder does not get removed. is it a mistake by me or a bug?

did/can anyone else test this?