Here we go again…
After SU6 the sim is not recognizing airports modifications made by the SDK Scenery Developer tool.
For example, I add several gates at KMDW and after loading a couple of times, I was unable to load those positions, nor objects, is just like if the sim doesn´t read my scenery. It happens to me at MMMY and some other sceneries.
Not to say that after SU5, gates disappear when you try to tweak them. You have to enable/disable the shadow cast option to seem them every time you rotate o translate them.