Hello,

I have been looking into your question and I can suggest you handle the ‘ExecutingCommand’ event and implement the following functionality  in its body :

   private void xamMonthCalendar1_ExecutingCommand(object sender,Infragistics.Windows.Controls.Events.ExecutingCommandEventArgs e)
        {
            if (Mouse.LeftButton == MouseButtonState.Pressed && xamMonthCalendar1.SelectedDate.HasValue == true && Mouse.Captured == xamMonthCalendar1)
            {
              e.Cancel = true;
            }
            if (Mouse.LeftButton == MouseButtonState.Released )
            {
                e.Cancel = false;
            }
        }

This way when you select a day and move the mouse out of the calendar panel, the month will not be changed.

If you need any further assistance on this matter, feel free to ask.