looks to me as though it does nothing! This code is obviously
just in here at the moment as an incomplete debug operation. The
trace statement simply records that the handler has been entered. I
imagine that the intention was to do something with the
ArrayCollection object _files, but at this point the intention has
not been realised. At a guess, the collection is supposed to be
populated in some way from the event object passed to the handler,
but that is just a guess.