@Override protected void invalidated() {
                    final double THRESHOLD = get();
                    if (!isBound() && (THRESHOLD < getMinValue() || THRESHOLD > getMaxValue())) {
                        set(clamp(getMinValue(), getMaxValue(), THRESHOLD));
                    }
                    fireTileEvent(RESIZE_EVENT);
                }
Sets the threshold of the tile to the given value. The value
will be clamped to the range of the tile.

@param THRESHOLD
src/main/java/eu/hansolo/tilesfx/Tile.java