The behavior of the Color Selector has changed between ArcGIS 9.2 and 9.3 due to the fact that its behavior in 9.2 resulted in several issues. These issues resulted in color values changing depending on the color selected, the color space last selected on the Color Selector, and the color space set on the Advanced Selection dialog box.
Not all colors physically reside in all color spaces. In the following example, the RGB color space outlined in yellow and CMYK color space outlined in blue do have areas that do not overlap; HSV is similar in that it has colors that cannot be represented in other color spaces.
Because of this, if a color is set in one color space and the color space is changed, the effective color may change because the original color cannot be properly represented in the new color space. At 9.2 and previous releases, the Color Selector would present the color space last used to define a color the next time the Color Selector was opened. Because the Color Selector was not representing the correct color space, values could be chosen that could not be properly represented in the displayed color space, and when the color was saved by clicking OK on the Color Selector, the values would be changed to fit in the color space that the color was originally stored in.
At 9.3, this inconsistency was resolved by always showing the color space of which the given color was originally set. For example, all of the colors in the symbols included with ArcGIS Desktop are in the RGB color space.