final String WINDOW_GEOMETRY_PREF = getClass().getName() + ".geometry";
public void placeOnScreen(HistoryBrowserDialog dialog) {
WindowGeometry geometry = new WindowGeometry(WINDOW_GEOMETRY_PREF, WindowGeometry.centerOnScreen(new Dimension(850, 500)));
geometry.applySafe(dialog);
Point p = dialog.getLocation();
while(hasDialogWithCloseUpperLeftCorner(p)) {
p.x += 20;
p.y += 20;
}