Script Summary: Replaces the Facebook favorites-icon with the one provided by the application you're using. Now you know which tabs contain your apps and which ones are actually good, old Facebook!
If you're a fan of any Facebook applications you'll know how confusing it is to see a bunch of Facebook icons in your tabs, leaving you to guess which tab is which. This script replaces those icons with those corresponding to the application on that page, so you can tell the difference! Now Facebook still uses the Facebook icon and every application uses its own!
