It's not what I would call invisible, but yeah that's the behaviour I would expect. That's also similar, to what already happens when I type in one window, while I scroll in another.
Or on top of each other, so yeah it would only work, if at least one of them is not maximized/fullscreened. (And none has holes in the right places, but I have yet to see a program, that makes an actual use of this.)
