It seemed like object placement in the mission builder was going fine.. but then I noticed that when I actually load and fly the mission, my added scenery isn't showing up. When I load up the ObjectTool I can see the scenery, with boxes around the pieces. But as soon as I close the ObjectTool .. whether I have saved changes or not.. the scenery disappears and I am back in the mission. Anyone have any idea what I am doing wrong?

The solution appears to be not closing triggers .. I am fairly sure you can't just enter a bunch of triggers and wait til later to use them...

That would do it, alright...but it should also cause an error message.