Is there any reason why the runways of some airfield disappear as you zoom out, while others remain? It's a bit irritating when planning long journeys because you can't select the airfield as a starting waypoint at the desired levels of zoom (1:560,000 in my case). All you see is a coloured circle which denotes the ATZ. Airfields affected include Netherthorpe, Wickenby, Clacton and Derby on my copy of Skydemon (2.4.2.16291)