Macoslib and NSDatePicker

I have been investigating the use of NSDatePicker and have noticed an anomaly.

In ObjectiveC/Cocoa if you have an NSDatePicker mixed with text fields you can tab from one to the next and when you return to the date picker it highlights the first section of the date, so if the date picker contained 01/02/1952 it would highlight 01 ready for your action.

I cannot find anyway for Macoslib to have this functionality.

Does anyone know please how it can be overcome?