The MonthCalendar control can made to PopUp on the screen, like a PopUp
menu. To use this feature, call the DropDown method of the control.
You must provide the X and Y location in screen co-ordinates to this
method, where the Control will PopUp. Optionally, you can specify an
Animation effect that the control will use during popping up. The available
Animation effects are Blend In, Slide Down and Roll Down.
The control checks if the specified location is too low and part of
it will be out of the screen. In that case it shows up above the specified
location. The ParentHeight parameter of the DropDown method can be used
to specify the height of the Parent Control, so that the Control won't
block the parent if it Pops up above the specified location.

MonthCalendar PopUp Example