When using the spam cleaner, if when you leave the "Check spammer's IPs" checked, the second modal box with the IP check appears, and you can use the close button to dismiss the modal box normally. The page that spawned the modal box remains unchanged. If you uncheck that spammer IP check, the spam cleaner modal box disappears, but it forces a page refresh (no matter what page you spawn the cleaner from, whether it's the admin CP or the front end). This can get aggravating when you're trying to clean many spammers, and rather defeats the purpose of the modal window. I believe this is a bug - the spam cleaner window should behave the same way whether or not you're checking spam IPs.