My solution consists of 2 executable projects and a couple dlls. Project1 is a Smart Device Project, Project2 is a Windows Forms Project.
Both projects use the same libraries, the reason of that is I want to test my libraries on PC before I deploy it on the device.

The problem is that the DLL project type can be Smart Device Class Library or Class Library, not both. I cannot add a reference from SD project to WF and vice versa. I was able to add reference from SD project to a dll file (generated from Class Library project) instead of the project itself, but for some reason I got the message "cannot load XXX type from YYY assembly". It doesn't depend on my code, because when I created separate project for the same sources, everything was fine.

The only solution I've found is to create 2 types of projects for each library, but I don't know how to make 2 projects based on the same sources.