The color tool is made to work simulataneously with Foreground Color and Background Color. Use the Left Mouse Button to select the Foreground Colr for your art. Use the Right Mouse Button to select the Background Color for your art. The Foreground and Background colors will be active whenever you draw filled rectangles or circles. By drawing shapes using the Right Mouse Button, the Fill and Line reverse. Try various combinations of colors and mouse clicks to learn the power of this tool.