It works fully automatic and in the background and the only way to notice that a popup window has been closed, is if you choose to activate the sound notification which will sound every time a popup is closed.
Main Popup Assassin Pro features:
Popup Assassin Pro is very fast and small;
Works best at blocking popup ads when using Internet Explorer;
Kills unwanted popup ads before they open;
Configure sites to block;
Allows to open any killed window from Popup Assassin Pro log;