title: C# static List<> has item but cannot access it
body: <p>Following NullReferenceException throws when ChildFolders() gets called. In the bottom of the picture, one can see that at least one desired Folder exists. But trying to access them doesnt work. How does this happen?</p>
  
  <p><img src="https://i.stack.imgur.com/DOA3R.png" alt="Following NullReferenceException"></p>