Hey devel.bmad -
So if you look at the master material the Object position is broken up with a Frac. A Frac node will return only the decimal of the value inputted, so for instance if you have a value of 100.456 then Frac it you will only get .456. Since most everyone has the snaps on you will not move by any fractional amount but instead in values as low as 1 but the fraction amount remains the same. If you turn snap off or move by typing in an amount, the book will change color.
Thank You
Eric Ketchum