I wanted to look at a small file that was over-written a month or so ago. I clicked on 'Deleted Files' (via the web interface) and see some files there. When i entered the name into the search box, nothing was shown.
To make sure that I was doing things properly, I scrolled down in the 'Deleted Files' list, saw a file from a few weeks ago, and entered part of its name into the search box. Again, nothing was shown.