Color picker default behavior? Just a theoretical question here.
Why is the color wheel selector in blender white in the center? Is there any reason not to use the neutral colors that usually are in the center of the color wheel?
You can change the color selector type in the user preferences.
To open user preferences, press CtrlAltU then under the System tab change the Color Picker Type. I think you may be looking for the Circle (HSL) type.