Sometimes when I start typing quickly into the Find box in the Library, the library refreshes before I finish typing and when that happens the Find box loses focus, so that the rest of what I type ends up disappearing into the ether. I have to click back in the Find box to bring the focus back there and finish what I was typing. I can't reproduce this consistently when I try, but it happens often enough to have become irritating. Maybe you need to wait for a slightly longer idle time in the user's typing to prevent this from happening.
