I used to put all my third-party libraries in a folder: d:\lib. If I created a new directory under it, and put some new library in that directory, I found that IDEA cannot recognize the changes to the directory immediately. Even the "refresh" button in the dialog don't work. I have to open and close the dialog several times, waited about 1-2 mins before the changes were detected.
My system configuration is : IDEA 10.0.3, windows 7.