OpenFileDialog can't see partitions in My Computer

Hello!
I'm learning to create windows applications in C#. I use Net Framework v3.5 compiler csc.exe. I tried to make a simple notepad and everything was ok until I wanted to use FileOpenDialog. I write:

OpenFileDialog dlgOpen=new OpenFileDialog();     dlgOpen.Filter="Text Files (*.txt)|*.txt|Microsoft Word Files|*.doc|All Files (*.*)|*.*";     dlgOpen.ShowDialog();

It works ok, but I don't know why it doesn't show partitions and drives in My Computer window. Screen:

(Sorry for Polish names, I'm a Pole. "Otwieranie" - "Opening", "Mój Komputer" - "My Computer")
What have I done wrong? Help, please.