The Twitter for Mac OS X application has a secret preferences tab. This gives you access to options like: Show full names, Compose windows float over all windows, type anywhere and munch more.
Close the Twitter for Mac OS X App en type the following defaults write command in Terminal:
defaults write com.twitter.twitter-mac DebugMode -bool true
Restart the Twitter application, the secret settings panel is now available in the Settings menu.
Disable the secret settings with:
defaults write com.twitter.twitter-mac DebugMode