DLLs referenced in a project used by another project in .NET

There are many similar questions but they don't seem to make too much sense of my specific problem.

I have a project A, a class library which references an external DLL

Microsoft.TeamFoundation.WorkItemTracking.Client, 
Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a

Project A compiles fine - I set the referenced DLL to copy local and left Alias untouched as global.

Project B references Project A and everything is just dandy, except at the end of the compilation, I get开发者_开发百科:

Error 5215    The type

'Microsoft.TeamFoundation.WorkItemTracking.Client.WorkItem' is defined in an assembly that is not referenced. You must add a reference to assembly 'Microsoft.TeamFoundation.WorkItemTracking.Client, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. C:...\Content\Status.aspx.cs 9 13 ProjectB

Everything is in the same solution file. What am I missing in this case? The reference of Project A from Project B is done via Project reference.

I this the feared dll hell I keep hearing about?

Does project B use the WorkItem class? Is it returned from a method in Project A?

If that's the case, then the DLL containing that class needs to be referenced by project B. How else could project B declare an object of that type, or call the methods of that class?

Project B uses that DLL directly, so that project needs to reference the DLL as well.