Files are copied to a new application only when that application is created. If a change is made to a file in an underlying layer at a later time, then that changed file will not be copied to any of the applications based on this layer. This avoids the danger of losing changes that might have been made in the child applications.
This does not mean that no change made to an underlying layer will ever be seen by an application based on it. The following changes to an OEM layer will propagate through to child applications:
• Changes to any configuration variables that are not found in the child application’s copy of the configuration file.
• New tag types added to the OEM layer.
(Be careful: tag instances are not propagated. Tag types are.)
• New pages are not copied to the child application, but they can be seen.
If you add a new page to an OEM layer application, then open the child application, you will be able to add that page to the child application’s menu and view it. You will not be able to edit it within the child application since the page file does not become a part of the child application.
You will need to re-start the child application before these changes will be seen.