The 'proportional' flag of RadialGradient is not used. It is passed to the prism RadialGradient constructor, but there is no corresponding member in prism's RadialGradient. Also, the flag makes no sense since there is no start and end value in RadialGradient.

    /**
     * Indicates whether start and end values are proportional or absolute.
     * If this flag is true, start and end values are defined in a [0..1] space
     * and will be scaled to match the size of the shape that the gradient
     * fills. If this flag is false, then start and end values are absolute
     * coordinates.
     *
     * @profile common
     * @defaultvalue true
     */
    private boolean proportional;