The Color Picker tool samples a color, displays it along with its hex value, and optionally changes the current foreground color to match it.
Color Picker Settings
This option will allow the color to be sampled from all available layers. The resulting color will be a composite of all layers, not just the current one.
The Sample Average option will take the color sample from a radius which is set by the slider. The resulting color will be an average of all colors found by the tool to be inside the radius.
This toggle will activate the capturing of the selected color by the foreground color well in the Toolbox .
Default Keyboard Shortcut: O