I found out that using Expose to reveal your desktop has an interesting effect. I used Safari and then activated Exposé. The status bar was still visible at the upper edge. Now, when I moved the cursor over the desktop, the status bar changed. What has happened? Well, when I reached the point where the MacPolls link was located in the Safari window, the status bar showed "Go to www.macpolls.com", when I moved the cursor around, I could see the staus bar change to what it should when the Safari window was visible (but it wasn't, as I saw the desktop). Now, what does this mean? It seems, that the Safari window worked as if it was still in the foreground, but why?