There is a solution from several projects. References indicated from the first and third to the second (the first is in the solution directory, and the third is not). I put using namespace TransCore; , the Link and Node classes from the main project directory are available, but all the classes / interfaces in the subfolders do not exist, although they are declared in the same namespace. Why so, and how can I fix it?
UPD. For the first two projects, right-clicking opens the following menu:
And the third is:
How are they so different? That the third is out of the solution directory?


