PrimaryFlightDisplay added but gets no data!

Hi Michael, maybe I am too silly for Qt but can you see why my PrimaryFlightDisplay gets no data  (attitudeChanged etc)?
It is supposed to get its different slots connected to the UAV instance's signals at PrimaryFlightDisplay::setActiveUAS() . . This also gets called, when connecting a UAV (eg the simulation one). However my slots never get called, is there something simple I might have overlooked?