//======================================================================
// -- initialize the display --
//======================================================================
setSize(900,650);
setItemSorter(new TreeDepthItemSorter());
addControlListener(new DragControl());
addControlListener(new ZoomToFitControl());
addControlListener(new ZoomControl());
addControlListener(new PanControl());
addControlListener(new FocusControl(1, "filter"));
addControlListener(new HoverActionControl("repaint"));