User made folders, heres an example scenario.
I unzip something or copy over a file to another folder. copy/unzipping is done.
I delete the folder/file that was recently used. It tells me that the file / folder is used and can only be fixed by rebooting.
This is nothing related to special permissions on the folder.
Another example is i delete a folder thats been made for ages, and it tells me access is denied... all of these are user created folders.. this happens quite often on all of the Windows 7 installation's ive ever made... I cant imagine MS never fixed this issue.. this was not on XP or Vista.