Why C# projects always open up expanded to show all files

Question

I have a solution that has a large number of C# projects. When I open the solution, all the files for all the C# project are expanded. Note that all the C++ projects open up collapsed. Does anyone know how to force the C# projects to also open up collapsed? P.S. I cannot include the .user, .suo, and .ncb files when I submit the files into revision control, but that appears to be the only way VS2005 remembers to collapse the C# projects.