VS 2008 OpenFileDialog Control That Will Read A Text File Into Memory - When Select All Files *.* It Does Not Re Appear?

I am writing an application that will use a OpenFileDialog control that will read a text file into memory and later process it.

I do have the following filter: Text files (*.txt)|*.txt|CSV files (*.csv)|*.csv|Spaced Text files (*.prn)|*.prn|All files (*.*)|*.*"

When I navigate to my test folder that contains a single .txt file, I see that file. When I change the filter to *.cvs that files goes disappears because it has a .txt extension. That is good. But when I select All files *.* it does not re appear? Why and how do I make it appear.