Sorry, but it didnt help... Really dont know what to do :-(( stupid sessions :-(( when i move a building to a layer session it DISAPPEARS :-( How to work with sessions? :-(
Layers are like having two different editing modes. They allow the route, with the track, texturing, and buldings that are permenant to be in one place. Other items such as settings for industries, rolling stock (consists, wagons, etc.) are placed in the session because they're not permenant.
Now having the layers has an added advantage. With layers you can show the route in different time periods. Yes, track and buildings can be placed in a session layer, and the session can be saved with a different name. This allows for some track and buildings to be in a place that aren't there now, or weren't there when the line was originally built.
You can transfer objects between layers by selecting them and changing from route to session, or creating your own layer. This allows you lock down objects so that things can be moved around the objects, like adding in extra trees or street lights for example, without disturbing something that's already in place.
Now there is one thing that can prevent settings and edits from being saved. Ensure that the program was installed and is running as Administrator if you are using Windows Vista or Windows 7. This will ensure that the program is allowed to write to the folders and save your changes.
Hope this helps explain what the layers do.
John