@Override
    public void layoutContainer(Container parent) {
      int width = parent.getWidth();

      int height = 0;
      for(Component c: parent.getComponents()) {
        if (c instanceof PaletteGroupHeader groupHeader) {
          groupHeader.setLocation(0, height);
          if (groupHeader.isVisible()) {
            groupHeader.setSize(width, groupHeader.getPreferredSize().height);
            height += groupHeader.getPreferredSize().height;
          }
          else {
            groupHeader.setSize(0, 0);
          }
          if (groupHeader.isSelected() || !groupHeader.isVisible()) {
            PaletteComponentList componentList = groupHeader.getComponentList();
            componentList.setSize(width, componentList.getPreferredSize().height);
            componentList.setLocation(0, height);
            height += componentList.getHeight();
          }
        }
      }
    }
@Override
    public void layoutContainer(Container parent)