I am afraid that there is no easy way to determine whether the click comes from the NavigationPanel or from a header in the MonthViewDefinition as the same command is used in both ways. You could customize the TimeRulerItemStyleSelector
of the ScheduleView and more specifically the TimeRulerMonthViewItemStyle and TimeRulerMonthViewTodayItemStyle Styles - the button which switches from MonthViewDefinition to DayViewDefinition is placed in their templates. You could replace the command of the button with a custom one with additional logic for determining the source of the click action.
I hope this is helpful. If you have any issues/questions with the approach, let us know.
the Telerik team