Color Selection Tool
The Color Selection Tool is used to select pixels that contain a specific color or range of colors across the entire picture.
Position the mouse cursor over a pixel that contains the color that you wish to select and click left mouse button once. The selection area will contain all pixels in the picture that match the color of the selected pixel.
To broaden the scope of the colors included within the selection, increase the value of the Color Tolerance setting. A setting of zero will select only those pixels that exactly match the color that you clicked. Higher settings will expand the selection to include additional pixels with colors that fall within the tolerance range.