In comparison to traditional ways to install applications and other application delivery methods that have been around for quite some time – such as application virtualization – application layering technology is still in its early stages. Because app layering is relatively new, tools for editing existing layers are unfortunately sparse.
You might ask, “Why would I need to edit an application layer?” Well, you could find yourself needing to edit registry keys for an application layer because you want the application to behave differently. So, how would you edit registry keys for a layer that is already created? The default answer for all layering vendors (assuming they can even edit layers, you should ask!) is to put the layer back into capture or packaging mode and make your registry changes there. Sure, this will work, but this is a “sledgehammer” approach when a “scalpel” may be better. When you put a layering tool into capture mode, it records all changes that happen to the operating system. This is a bit heavy-handed when you’re only trying to make a single registry key change.