But today I installed GSX and after it all the default terminal building desappear. The program works fine in all his function, is just i don't understand what's happen with all the airports.
It simply not possible that installing GSX would make the default buildings to disappear. In fact, it would be nice if it was *possible* to have default buildings disappear in some what, which would save us from many griefs with default buildings conflicting with our sceneries.
But the fact is, there's no way to disable a default building, other than creating a specific exclusion .BGL file made for each airport that you want to exclude.
So, what you are reporting, is simply not possible with GSX, and nobody ever reported it before. The only things that GSX removes from the default scenery, are the default airport traffic vehicles, and they are only removed around the parking you just selected with GSX, but the vehicles are entirely different objects, handled by the AI engine, so it's not even theoretically possible that we could disable a default building by mistake when trying to remove a vehicle.
Are the buildings missing right from the start ? If yes, that would clearly prove GSX doesn't have anything to do with it, since it's not doing anything, until you select a parking to use with it.