The Workspace Virtualization Agent assigns an HKCR priority to each layer. If a system request applies to more than one activated layer, the system uses the layer with the highest HKCR priority. If two activated layers have the same HKCR priority, you cannot predict which layer the system request accesses. To resolve this problem, you can set a layer's HKCR priority.
Prioritization works as follows:
For example, you have activated layers for two different Web browser applications. Both applications are registered to open HTML files. You can assign a higher priority to one of the layers so that it is used to open the HTML files.
For each system request, the Workspace Virtualization Agent does the following in order:
HKCR (HKEY_CLASSES_ROOT) requests are based on file type. For example, the system would make an HKEY_CLASSES_ROOT request if a user clicked on a text file. If the request involves a process, the Workspace Virtualization Agent also takes into consideration the owner layer of a process. The owner layer of a process is the layer that houses the executable file that starts the process. The owner layer of a child process is the same as the owner layer of its parent process. The owner is the same even if the executable file that starts the child process is in a different layer.
Table: Layer priority values
For example, you have an activated layer for Firefox with Internet Explorer installed on the base layer. When you open an HTML file, the Workspace Virtualization Agent does the following in order: