IDEA maintain a lock on directory after closing project?

B6963,
WinXP SP2
JDK 6 (used to run IDEA)

Anyone seen this before? I've had this happen to me a number of times:
I open a project, close it, and then attempt to rename the directory from Windows
Explorer and an error message pops up stating that another process is using the
directory. At this point I need to restart IDEA for the lock to be released.

Cheers,

Bonny