Yeah, it's an imperfect piece of software, but it's in that "just good enough" area for this particular job. I'm happy that it's working out ok for you.

By the way, you don't actually have to change the extensions -- that just makes them show up in the default file views. If you change the filter to "All files" and select a file with an MXF extension, it tries to open it and goes "Oh! I know what to do with this." At least, that's what I found.