@magicalclick: but I can create a desktop application that hides the taskbar even if it's set to be always on top (it's not even hard, a borderless, caption-less, maximized window does the trick). I can also create a desktop application that doesn't appear in the taskbar (and e.g. control panel applets have never appeared there as far back as Windows 95). I don't think it has ever worked the way you describe.