Color Boxes and Modes
The foreground color appears in the upper color selection box and represents a color that is currently active. The background color appears in the lower box and represents an inactive color.
To change the foreground color, click the upper color selection box in the Toolbox.
To change the background color, click the lower color selection box in the Toolbox.
To reverse the foreground and background colors, click the Switch Colors icon (the arrow) to the right hand corner of the boxes..
To restore the default foreground and background colors, click the Default Colors icon (the little black and white boxes) to the left hand corner of the boxes.
Note: If you are using the Gradient Tool, the currently selected foreground and background colors will be the default colors of the gradient.