It depends on how you set the WeekStarts property. In the latest version in the sandbox (5.7.1914) at www.daypilot.org/sandbox/Month/ it seems to work correctly: The WeekStarts is set to Sunday, the first day of the first visible week is Sunday, Nov 1, 2009 (VisibleStart) and the last day of the last vislbe week is Saturday, Dec 5, 2009 (resulting in Dec 6, 2009 00:00 as VisibleEnd).
What is your setup, especially the WeekStarts value?
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