NSDatePicker problem with NSDatePickerMBS

For a pure OS X project, I wanted to use the original NSDatePicker and turned to Christian’s classes because I like the visual clock representation.
In this case, I have placed the control on a PopUpViewController and the result surprises me a bit: The am/pm strings draws way off to the right of the clock. If anyone of you should use the native control too: Do you have any idea if this could be caused by me running the current beta of OS X, by placing it on a popupview or, well whatever?