Add multiple projects in one solution file in Visual Studio 2008

For some inexplicable reason, my fresh installation of Microsoft Visual Studio 2008 Professional Edition seems to be unable to work on multiple projects in a single solution file. I remember there is no such problem for all its earlier 2005 editions and 2008 Team System edition. This is annoying!

To fix this, all you need to do is:

Click Tools → Options → Projects and Solutions → General → Check ‘Always Show Solution’

Please do not ask me why this is not the default because this is equally puzzling to me.