The scrollable window shows the declaration of two float arrays, rgb and hsv. You can change the components of either array and, in turn, change the current color. To change one of these parameters, place the mouse over the value and with the left button down, drag the mouse up and down. The display window with the two color models and the technical window showing a swatch of the selected color will be updated accordingly.
While an input item is selected (drawn in yellow), you can also change its value using the Up-Arrow and Down-Arrow keys. The amount added to or subtracted from the selected item is fixed within the program. However, a multiplier is also used in making the change. You may adjust the multiplier through the Page-Up and Page-Down keys. Making the mulitiplier larger accelerates the change that is made to the selected item.