I think the Refresh behavior in the File Chooser has been broken since v10.0. You'd download a new open source JAR. When trying to add it as a library, IDEA wouldn't display the new folder no matter how many times you clicked on the Refresh button in the file chooser.
I recently upgraded to IDEA 10.5.2. While the file chooser was open, I added a directory using Windows Explorer. I then clicked refresh to verify the new folder would show in the file chooser. To my delight, the new folder appeared just as I expected!
Thanks for the fix to this minor, but annoying, issue.