I notice that the Smooth Tasks widget is working in KDE 4.7. However there is no longer a preview window when I hover the mouse pointer over an icon on the Panel (cf. old screenshots posted by ReemZ
in the post Re: Small panel buttons? [Solved]
): instead a pop-up bar appears with the name of the window in it. But at least small icons for minimised windows on the Panel are available again, rather than the long bars for minimised windows that the Task Manager widget puts on the Panel.