(for those synced with Google Calendar) Currently, if you create an "all day event" (one of those that appear as a label on top of a day and not as a specific time slotted event), when the event gets synced to the main Google Calendar it automatically marks the entire day as "busy". You have to go into Google Calendar to change this by individual entry. This ends up blocking Google's automated scheduler from scheduling client meetings on that day as a result. The problem is that it doesn't tell you this or show this in your calendar... it just says it's not available for booking in the scheduler without indicating why. Took me forever to figure out why I had a bunch of fully "busy" days unavailable for booking.