public RectangleConstraint toUnconstrainedHeight() {
        if (this.heightConstraintType == LengthConstraintType.NONE) {
            return this;   
        }
        else {
            return new RectangleConstraint(this.width, this.widthRange, 
                    this.widthConstraintType, 0.0, this.heightRange, 
                    LengthConstraintType.NONE);