Window Style
To select the style in which the window title bar and any window borders of docks are drawn, choose one from the popup menu.
Aqua
Window title bars of docks are drawn in the System style for utility windows and accoding to the setting chosen in the Appearance section of the System Preferences.
Metal
Window title bars and window borders of docks are drawn in the Metal style.
Translucent Black
Window title bars and window borders of docks are drawn in a translucent black style.
Translucent White
Window title bars and window borders of docks are drawn in a translucent white style.