public void onSliderInput() {
   if (mySlider != null) {
     setSliderValue(mySlider.getValue());
   }
   if (changeEventHandler != null) {
     changeEventHandler.fireActionPerformed(this);
   } else {
     ((EuclidianStyleBarW) app.getActiveEuclidianView().getStyleBar()).fireActionPerformed(this);
   }
   fireActionPerformed();
   updateGUI();
 }
 /** @return {@code int} or {@code -1} if the {@link Slider slider} is null */
 public int getSliderValue() {
   return mySlider == null ? -1 : mySlider.getValue();
 }