windows.
the slidingpopups effect adds its managed windows to the ignored list of
the fadeeffect, making them mutually exclusive
svn path=/trunk/KDE/kdebase/workspace/; revision=1021321
a number identifying north/south/west/east and a screen coord) will
appear with a slide animation.
used for popups that come out of panels
svn path=/trunk/KDE/kdebase/workspace/; revision=1001604