Is this a Nautilus bug?

[Santanu Chatterjee]

Hi all,

Can you tell me what Nautilus uses to detect file types?
I ask this because a very strange thing happened today.

I downloaded the entire set of plain text howtos in tar.bz form
from tldp.org, and unzipped and untarred it in a directory.
Then I opened the directory in Nautilus and clicked on a file
but Nautilus said "Couldn't Display <filename>". Apparently,
Nautilus could not determine the file type. Using 'file' in a 
terminal, I got this:
------------------------
santanu at ubuntu:~/HOWTOS$ file IO-Port-Programming
IO-Port-Programming: ISO-8859 English text
------------------------
Even when I explicitly selected gedit to open the file from the
"Open With Other Application" menu option, it said: "Could not
add application". 

Strangely enough, when I renamed the file by adding a .txt extension,
Nautilus opened it using gedit without any problem at all!!

What is wrong with Nautilus? Is this a bug or is this intentional?
It reminds of the quote in The Art of Unix Programming:
     But the day Linux gives the Mac diagnostic that you can't open 
     a file because you don't have the application is the day Linux 
     becomes non-Unix.
                          -- Doug McIlroy

Regards,
Santanu Chatterjee