InitialFirstResponder on NSPopUpButton

Hello,

I‘m trying to create an app with one NSPopUpButton and two NSTextFields. The first control is the NSPopUpButton and I want to make it the initialFirstResponder. When the app starts, it always skips the popUpButton and the focus is on the first textField. I already tried to subclass the popUpButton and to override canBecomeKeyView.

Maybe someone has a hint. Thanks.