Hello Brad,
1. You can change this behavior by creating your custom skin based on the one you use.
Then you should change the image which is used to paint the drop down button.
2. If you are using Windows Vista or Windows 7 and using themes such as Aero, then the properties that modifies the color of the calendar has no effect.
NDateTimePicker control derives from the standard DateTimePicker control and the colors of the calendar are set to a palettes colors in ApplyPalette virtual method.
Currently, the following calendar colors takes their values from palette:
CalendarForeColor = Palette.ControlText;
CalendarMonthBackground = Palette.Control;
CalendarTitleBackColor = Palette.ControlDark;
CalendarTrailingForeColor = NColorHelper.ToGrayScale(Palette.ControlText);
You can add additional colors by overriding ApplyPalette method.
Of course all, these settings will take effect if you are running it on windows XP or the visual styles of your application are not enabled.
Best Regards,
Nevron Support Team