Useful for those who use it to pull flash video, etc., out of websites...

Set Safari's Activity window to have items collapsed by default (http://hints.macworld.com/article.php?story=2012062809141258)

Safari has a setting that controls this behavior, although it isn't accessible via the GUI.

Simply type the following in Terminal to make the Activity window open with all sites collapsed by default:

defaults write com.apple.Safari ActivitiesStartExpanded -boolean NO

(MacOSXhints (http://hints.macworld.com/article.php?story=2012062809141258))