OK, I've reinstalled FTX SCA, made the Orbx recommended file changes and all seems to be well, except that, at ground level and probably up to about 100 feet above the ground, what appears to be the default runway, ground etc without any markings is appearing above the FSDT runway, ground. This is noticeable on takeoff and landing and there is flickering as the default ground transitions to FSDT. Any ideas? I have also asked the question of Orbx.