I noticed just now i changed the month on the Calandar (in the settings section) from November to December because there wasn't even any boxes left to check in November! When i did this (even though i didn't click save) the box to select days off went away (so i can't change them for a week - even though i didn't touch the days off). I think days off and vacation should be seperate (at least so changing one doesn't make it think you changed the other).