If you have ever updated the password in an entry, then wanted to go back and see what the old one was, here is how to do that.
Open the Entry Window. Below the hidden (scrambled looking) password filed, there is a Show password history link. Click that and a small window will popup with the list of all the passwords that that entry has ever had.
You can select and copy anything you need to, delete it, or just click OK and the popup will disappear.