code: public ObjectProperty<MouseButton> panButtonProperty() {
  		if (this.panButton == null) {
  			this.panButton = new StyleableObjectProperty<MouseButton>(DEFAULT_PAN_BUTTON) {
  				@SuppressWarnings("synthetic-access")
  				@Override
  				protected void invalidated() {
  					final MouseButton button = get();
  					if (button == null) {
  						set(DEFAULT_PAN_BUTTON);
  					}
  				}
  
  				@Override
  				public CssMetaData<ZoomablePane<?>, MouseButton> getCssMetaData() {
  					return StyleableProperties.PAN_BUTTON;
  				}
  
  				@Override
  				public Object getBean() {
  					return ZoomablePane.this;
  				}
  
  				@Override
  				public String getName() {
  					return PAN_BUTTON_PROPERTY;
  				}
  			};
  		}
  		return this.panButton;
  	}
docs: Replies the property for the button that serves for starting the mouse scrolling.
  
  @return the property.