I have the same problem, DayPilotMonth control (latest version).

Take this event, for example:
[start] 2011-06-12 00:00:00.000
[end] 2011-06-14 00:00:00.000

It only shows the event as being on the 12th and 13th. If I add 1 second to the end_dt, it shows up correctly (spanning all three days).
Is this somehting you'd consider a bug or is there a known fix? Our system stores event end dates in that format because they're not tracked by time.

The difference between the calendar in http://www.daypilot.org/demo/Calendar/ and my calendar is that, the demo calendar ends at 12am for a day in a column, but for my calendar the column for each day extends over 12am. There for when I drag the slots over 12am, i face the problem.

@Allen: This is by design. DayPilot Month works with exact DateTime values, that's why 2011-06-14 00:00:00 doesn't belong to 2011-06-14. What you are looking for is an equivalent of DayPilotCalendar.AllDayEnd. This property says whether the end of all-day events is stored as DateTime or Date. I'm adding it to the wishlist for the next release.

@Anonymous: I will check the behavior with DayBeginsHour set.

Dan, thanks. I'll see if I can just add a second to my end times for now.