The leading FF or 00 are non-functional. I guess they added it to go from 24bit to 32bit (24bit RGB color with 8bit alpha channel) but currently it has no effect. Where do you need hex colors? Strings only right. For those you need all the 8 characters.
Maybe they plan on adding text alpha channels? If that's true everyone with 00 leading a color string will get invisibile text strings.
*Mark for myself*...check the text strings and swap leading 00 with FF.