I you work on a modified source, some option might be disabled because some components are missing or altered. Now, there is a small bug in nLite (sorry for the word), I think... when an option is not available, it's greyed out but shows the default value as greyed out, not the real value. As for compatibility, I think you ned to keep the compatibility (not the player obviously) if you want to be able to insall WMP later.