I have a layout that I modified and saved. I just noticed that the copy is missing some buildings and objects but the original unmodified version of the layout has them in. How do I get the missing objects to show up in the copy of the layout? It's the Reading layout by Roon. I don't want to start over with the unmodified layout since I did alot of work to the copy and added a several mile DEM route extension to it. Help?