Let's say I have a simple hierarchy of Date dimension: Year - Month - Day.
As it is known the the Month has to have the keycolumns the month and the year. It would be a collection. Otherwise if it had only the month wouldn't work. For more info about that check this.
Now my question is:
When the orderby property is set to key, How does it know what key to get? There are two columns in the keycolumns property. How does it know it has to sort on the month number? What does the year column play in all this?