Steps to reproduce:

1. Open attached project
2. Make sure the default text editor is set to Visual Studio
3. Right-click the project window and click 'Open C# Project'
4. Notice the .shader file (which is under Assets\Resources\Shaders) can not be found in the Visual Studio's Solution Explorer

Workaround: Open the shader file manually by double clicking in the editor, then the shader code appears, but it will not be shown in the Solution Explorer.

Note: If the text editor is MonoDevelop, shader files are shown as expected.