The second selection had a tolerance of 25, and the third selection had a tolerance of 100. As you can see, the greater the tolerance setting the more pixels were included. The enhanced version was created by inverting the selection and applying a negative drop shadow, i.e. a minus sign was placed in front of the vertical and horizontal drop shadow settings. The Hue Match Mode chooses pixels based on their position in the palate. Hue is the actual primary color, i.e. Red, Green and Blue.
Lets take a look at an example.
In the above example the selection is rectangular. This is due to the way the pixels are aligned. Lets take a look at examples using the red circle and the surrounding blue pixels. In the above examples, the Hue Match Mode was used and the tolerance was set to 10. Notice how almost the entire red circle was selected when a pixel in the red circle was selected.