On 18 Jul 2017, at 03:35, Quincey Morris <quinceymorris@...> wrote:

On Jul 17, 2017, at 11:27 , Gerriet M. Denkmann <g@...> wrote:

The first time prefController is of course nil.
The next time it is not.

I would suggest that you look in the debugger at whether the window controller *has* a window the second time around.