Having a window which is `current' and `visible' but not on `top' gives rise to some effects of concern. For example, scrolling this current window is cause for massive load on the system; if there are windows on top, making them current requires hiding the current one (clicking on them is ineffective). My use for being in such a situation is, e.g., scrolling some acme body in the background while doing something with an rc window on the foreground (since my acme window takes up a large part of the screen).
Not particularly important, but an interesting case nonetheless, ak
