Using SourceLocationProvider.CollectMapping to create the mapping

Question

Hi all,

I'm trying to understand how to use SourceLocationProvider.CollectMappingmethod in C# .NET 4.0. The documentation in http://msdn.microsoft.com/en-us/library/dd987879.aspx mentions that the parameters are

1. rootActivity1, Type: System.Activities.Activity, description: A workflow element that represents an activity that is not mapped to a source location
2. rootActivity2, Type: System.Activities.Activity, description: A workflow element that shadows rootActivity1 but has specific source locations to which its members are mapped.
3. mapping, Type: System.Collections.Generic.Dictionary<Object, SourceLocation>, description: A dictionary object that contains a root activity and its descendants, each mapped to a source location.
4. path, Type: System.String, description: The path of the source file to use.

So my question here is for the parameter number 2, what does "shadows rootActivity1" term means?