@Override
 protected double computePrefWidth(double height) {
   int w = LayoutUtil.getSizeSafe(grid != null ? grid.getWidth() : null, LayoutUtil.PREF);
   return w;
 }
 @Override
 protected double computePrefHeight(double width) {
   int h = LayoutUtil.getSizeSafe(grid != null ? grid.getHeight() : null, LayoutUtil.PREF);
   return h;
 }