@Override
 public void storePreferences(Preferences prefs) {
   // app panel
   prefs.putBoolean("showPoints", appearancePanel.isShowPoints());
   prefs.putDouble("pointRadius", appearancePanel.getPointRadius());
   Color c = appearancePanel.getPointColor();
   prefs.putInt("pointColorRed", c.getRed());
   prefs.putInt("pointColorGreen", c.getGreen());
   prefs.putInt("pointColorBlue", c.getBlue());
   prefs.putBoolean("showLines", appearancePanel.isShowLines());
   prefs.putDouble("tubeRadius", appearancePanel.getTubeRadius());
   c = appearancePanel.getLineColor();
   prefs.putInt("lineColorRed", c.getRed());
   prefs.putInt("lineColorGreen", c.getGreen());
   prefs.putInt("lineColorBlue", c.getBlue());
   prefs.putBoolean("showFaces", appearancePanel.isShowFaces());
   prefs.putBoolean("facesReflecting", appearancePanel.isFacesReflecting());
   prefs.putBoolean("linesReflecting", appearancePanel.isLinesReflecting());
   prefs.putBoolean("pointsReflecting", appearancePanel.isPointsReflecting());
   prefs.putDouble("faceReflection", appearancePanel.getFaceReflection());
   prefs.putDouble("lineReflection", appearancePanel.getLineReflection());
   prefs.putDouble("pointReflection", appearancePanel.getPointReflection());
   c = appearancePanel.getFaceColor();
   prefs.putInt("faceColorRed", c.getRed());
   prefs.putInt("faceColorGreen", c.getGreen());
   prefs.putInt("faceColorBlue", c.getBlue());
   prefs.putBoolean("transparencyEnabled", appearancePanel.isTransparencyEnabled());
   prefs.putDouble("transparency", appearancePanel.getTransparency());
   prefs.putBoolean("facesFlat", appearancePanel.isFacesFlat());
   prefs.putBoolean("tubes", appearancePanel.getTubes());
   prefs.putBoolean("spheres", appearancePanel.getSpheres());
 }