Mouse over the palette to choose a color. Depending on which mode is selected, Ground, Block or Text color will change accordingly.
Click on a chip to select its color, which locks (or unlocks) current mode.
Alternatively, if supported, selection may also be controlled by pressing SHIFT + any key, and controls may be accessed directly as well by pressing the underlined key in their label.
Move selection in the Vision menu to check how colors are altered. Once an item is selected, "up" and "down" keys can be used for this purpose.
Compare main layout colors with a standard vision sample view.
Display (or hide) the palette or the sample view.