Why is .NET inconstent in calling directories "Directory" and "Folder"?

Question

If you want to do something with a directory/folder you use System.IO.Directory but if you want to display a dialog for browsing one you use FolderBrowserDialog?

Why is one named Directory and the other Folder?

Answer 1

Probably because the team that wrote the System.IO namespace was not the same team that wrote System.Windows.Forms.

Answer 2

Maybe because Folder in this case is rather a term of Windows(not only?) user interface than a definition of file system object.