LightweightSystem lws = new LightweightSystem(overview);
RootEditPart rep = getGraphicalViewer().getRootEditPart();
if (rep instanceof ScalableFreeformRootEditPart) {
ScalableFreeformRootEditPart root = (ScalableFreeformRootEditPart)rep;
thumbnail = new ScrollableThumbnail((Viewport)root.getFigure());
thumbnail.setBorder(new MarginBorder(3));
thumbnail.setSource(root.getLayer(LayerConstants.PRINTABLE_LAYERS));
lws.setContents(thumbnail);
disposeListener = new DisposeListener() {
public void widgetDisposed(DisposeEvent e) {
if (thumbnail != null) {