I've run into this before. You are correct in that the compiler is looking in Foobar.System.Windows.Forms because you named your namespace 'System'. The local namespace 'System' overrides the global namespace 'System'. I do not know how to get around this. In my case I chose not to name my namespace 'System' but instead named it 'Foundation'. I just wanted to let everyone know that therei s nothing messed up with your project.