I'm translating 8 idml files as a single virtually glued file.
Unfortunately, as far as I can see, there is no way of knowing which file I am working on. (I don't have InDesign, so I can't sensibly examine the idml files directly.)
This wouldn't ordinarily matter, except that there are a couple of issues I need to discuss with the customer, and she, reasonably enough would like to know in which file particular segments occur.
Personally, I like the way SDL Studio does this, with a clear marker between files, but just the filename above the segments display would also work.