[rhelv6-list] vim settings

[Red Hat Enterprise Linux 6 (Santiago) discussion mailing-list]

I have ~/.vimrc with 'set tw=120', but for one particular text file vim 
keeps going to the next line at the column 80. When I use vim to open a 
new file, this does not happen.

For this particular file, if I use vim -u ~/.vimrc then everything goes 
fine.  And if this file is renamed to a new file with an extension 
different than .txt, then vim works as expected ( new line at column 120 ).

I also deleted .viminfo but this does not help.

It must be something in vim that I do not understand. Any advice is 
greatly appreciated.

Thanks,
Vu