Bug 193465 Series color is incorrect in cone chart [0001]
Description: Series color is incorrect in cone chart. Build version:2.2.0v20070620-0630 Steps to reproduce: 1. Get the attached report design file, preview in layout. Expected result: The series is grouped by city, but the displayed plot color is inconsistent with legend color.
chart/org.eclipse.birt.chart.engine/src/org/eclipse/birt/chart/util/FillUtil.java
{
	/**
	 * Returns a darker color.
	 * 
	 * @param fill
	 * @return
	 */
	public static ColorDefinition getDarkerColor( Fill fill )
	{
		if ( fill instanceof ColorDefinition )
		{
			return ( (ColorDefinition) fill ).darker( );
		}
		if ( fill instanceof Gradient )