public void setLowerThresholdColor(final Color COLOR) {
        if (null == lowerThresholdColor) {
            _lowerThresholdColor = COLOR;
            fireTileEvent(REDRAW_EVENT);
        } else {
            if (!lowerThresholdColor.isBound()) {
                lowerThresholdColor.set(COLOR);
            }
        }
    }
Defines the color that will be used to colorize the threshold
indicator of the tile.

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